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TSF Dungeon is a transformation-focused dungeon crawler developed in RPG Maker MV.

The concept is simple, yet filled with potential: you take on the role of an adventurer delving into the newly discovered "TSF Dungeon", a mysterious, ever-shifting labyrinth rumored to be overflowing with treasure, monsters—and strange, identity-warping magic.

As you explore its depths, you'll battle bizarre creatures, uncover hidden lore, and experience involuntary transformations. But this isn't a game over. Even after being transformed—sometimes partially, sometimes completely—you can still continue onward. Each transformation unlocks new ways to play, altering your character's stats, abilities, and even how the world responds to you.

These transformations are primarily male-to-female (MtF) in nature, often involving a loss or reshaping of identity, and many lean into mythical monster girl forms. Whether you become a sleek harpy, a mischievous fairy, or a brooding wolfgirl, your journey doesn’t end.

✦ Features ✦

  • Transformation-Centric Gameplay
    A core part of the experience, with transformations affecting story, combat, and character interactions. Expect to change often—and unexpectedly.

  • Male-to-Female & Monster Girl Transformations
    The current version includes at least 8 distinct transformation paths, each with its own theme, appearance, and gameplay effects. More are in development.

  • Playable Transformations
    Transformations are not punishments. Instead of a typical game over, you adapt to your new form, unlocking fresh mechanics and strategies. Every form offers a unique playstyle, giving you new tools—and new challenges.

  • Unique Form Mechanics via Gauges
    Each major transformation introduces a specialized gauge system that directly influences gameplay. These gauges may track things like instinct buildup, emotional state, or biological changes—triggering powerful skills, passive effects, or even further transformations as they fill. Every form has its own rules, creating a distinct rhythm and tactical layer.

  • Identity Death & Narrative Transformation Themes
    TSF Dungeon explores the mental and emotional journey of transformation, including themes of identity loss, adding narrative weight to each change.

Note: TSF Dungeon is currently in active development. Content is expanding, with more transformations, storylines, and gameplay systems planned for future updates. 

If you enjoy TSF Dungeon and want to see more content, faster updates, and deeper transformation mechanics, consider supporting me on Patreon! Your support helps keep development moving and keeps me motivated to push the dungeon further.

Thank you for playing!

Changelog V0.2.3 

New Content

  • New Mermaid Form & Area Added the Mermaid transformation along with its dedicated area, equipment, and accessories. You can find this new zone at the seacoast just south of the Fairy area.
  • Underwater Breathing Mechanic When submerged, a new Breath Gauge will appear to track how long you can hold your breath. Running out of air may result in an instant transformation or being washed ashore.
  • Mermaid’s Dual Gauge System Mermaid form introduces two gauges:
    • Corruption Gauge: Functions like the other forms, tracking corruption buildup.
    • Breath Gauge: Works opposite of the base breath gauge. It fills while underwater and depletes when out of water.
      • In battle, the gauge also adapts: it fills during underwater fights and decreases during land battles.
      • At full gauge: corruption will slowly increase, similar to fairy dust effects in Fairy form.
      • At empty gauge: the player is forced to use certain skills, both in overworld and battles.
      • Gauge management: stepping into water tiles will refill the gauge, while leaving the water will drain it.
  • Water Breathing Potion New consumable item that prevents the Breath Gauge from decreasing while underwater for a limited duration.
  • Library Update Added Mermaid entry to the Library.

Bug Fixes

  • Fixed a bug where the player could transform back in quest-specific maps in Area 1, such as the Slime Chamber and Goblin’s Room.

Changelog V0.2.4 (Patreon Early Access)

New Content

  • Added a brand-new form with its own unique mechanics.
  • Introduced a quest-based Bandit Area that the player can fully explore.
  • Includes its own bad ending.
  • Bandits can now appear in the overworld after completing the Bandit Quest.
  • Added one new weapon as an initial test for the upcoming weapon update.

Adjustments

  •  Added a hint before entering the Fairy Forest.

Bug Fixes

  • Fixed an issue where the player was unable to transform back from Mermaid form.
  • Fixed a bug causing the player to always face north after fighting the Fairy Queen.
    • If this still happens, interacting with Alistair in the base should resolve it.
  • Fixed a bug where the Harpy Matron’s image didn’t disappear after the fight.
    • You can also Interact with Alistair if the issue persists.
  • Fixed an issue where the player would always get a Game Over when losing to enemies in Area 2.
    • You will no longer receive a Game Over in Area 2, regardless of boss progress.
  • Fixed a bug where accessories kept unequipping after leaving the base or closing the menu.
  • Fixed the swapped item descriptions for Mermaid Essence and Succubus Essence.
  • Fixed a bug where the MC in Wolf Form would be incorrectly identified as a Harpy in the Fairy Queen encounter.
  • Fixed a softlock where interacting with the Slime Mother from behind would trap the player.

You can find the Patreon early access here.

Updated 11 days ago
StatusIn development
PlatformsWindows, macOS, Linux
Rating
Rated 4.9 out of 5 stars
(11 total ratings)
AuthorCapek09
GenreAdventure
Made withRPG Maker
TagsDungeon Crawler, gender-bender, Monster Girls, NSFW, pregnancy, RPG Maker, Singleplayer, transformation
Average sessionAbout an hour
LanguagesEnglish
LinksDiscord, Patreon

Download

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Click download now to get access to the following files:

TSF Dungeon Ver.0.2.3 Windows.zip 487 MB
TSF Dungeon Ver.0.2.3 MacOS.zip 621 MB
TSF Dungeon Ver.0.2.3 Linux.zip 495 MB

Comments

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Viewing most recent comments 1 to 40 of 48 · Next page · Last page

You can get to the water orb directly by using the portal which meant to be the exit. I did this without knowing on my first try. It’s obvious that you’re in the wrong path once you see dialouges appearing in weird order. but if you are a person who saves often and use just one file to save, you will lose the playthrough.

All the wall with seashell are not solid and you can walk thru it. 

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is it just me or the wolf area is easier now at lvl 12-13. I was lvl 12 and the wolfmen deal 7 dmg. The previous version, they deal like 50-100+ dmg. what happend to the wolf area?

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Got this bug in goblin room puzzle. After I kill the slime on the correct trap, the trap glitch and make it into a bad one

There is a bug in this version where the Succubus and Mermaid Essence and Orbs have the same descriptions as eachother. Plus there is a bug that prevents the player from turning back into a Human after turning into a Mermaid. Mind you, I just learned these bugs are fixed in the 2.4 version, which is on Patreon, so I guess I'm getting on the Patreon. At least it is super dirt cheap to get that. Just $1. Wow. What an affordable deal. Absolutely worth it.

I don't exactly know what caused this bug, but after beating the wolf girl in the cave, I had the bleed effect. I tried using potions to remove it and nothing worked, even reverting the form didn't do anything. I tried turning into the other girls, and nothing worked until I turned back into the wolf, which then the bleed effect suddenly disappeared. I still don't know what caused it, but I feel it should be known

Thanks for the report!

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i was going to just ask what endings i was missing, but since other people will probably ask the same questions i have, i thought "why not list all the endings i do know and the dev can fill in the rest" so thats what im doing (i know the endings are numbered but i dont remember them)

1: become a slime girl, go to the slime room and follow all of Mothers commands

2: become a goblin girl, trigger the traps in the trap room twice, complete the final task for the goblin 

3: become a goblin girl, dont trigger the traps in the trap room, use the powder on enemy goblins/adventurers, return to the entrance

4: lose to Lilith 

5: reach 100% corruption as a succubus, enter the dungeon town

6: lose to the wolf girl

7: have 100% corruption when you reach the fairy queen

8: lose to the fairy queen

ive seen comments mentioning 100% corruption as the wolf girl and the town, but no matter what i do having 100% as the wolf girl does nothing for me, might be glitched

side note: it'd be neat if the adventurers could actually do something to you, like maybe since the generic adventure party is magic user, swordsman, axe guy and healer (as some call it, priestess) it'd be neat if they made you into generic healer #71 or something like that

edit: looking at old comments, i keep seeing people mention a "hero's quest/pendant" but i have ZERO idea what that is referring to. also when looking at the sprite sheet's for the MC there's 2 sets of sprites that i have zero idea if they're even used

(4 edits) (+1)

endings:

  1. ED #1 My Hero (be a female and enter the 2nd floor, continue to heal with the pendant, and enter the next floor each time, give greater heal)
  2. ED #2 Mother's Beloved (complete the slime mother quest) 
  3. ED #3 Goblin's Good Girl (do the goblin quest, fall to at least 2 traps in the goods room, plead to at least 3 people, give pleading)
  4. ED #4 Full-Fledged Succubus (lose against boss succubus - Lilith)
  5. ED #5 Inverted Goals (do the goblin quest, can fall at max 1 trap, transform 3 people, give magical dust)
  6. ED #6 The Den Sisters (lose against the wolfgirl boss)
  7. ED #7 Denbound Bitch (lose in the cave as a wolfgirl, after beating the wolfgirl boss and reaching 100% corruption)
  8. ED #8 harpy? (lose against the harpy matron?) didn't sucseed in finding it
  9. ED #9 The Green One Tries Her Best (lose against the fairy queen)
  10. ED #10 The Happiest Fairy (reach the fairy queen while in fairy form in 100% corruption)
  11. ED #11 The Pack Bitch (lose in the forest as a wolfgirl, after beating the wolfgirl boss and reaching 100% corruption)
  12. ED #12  none
  13. ED #13 The Midnight Girl (reach 100% corruption in succubus and enter the town)
  14. ED #14 Siren's New Voice (lose against the normal mermaids/merman)

ohh the harpy queen one is simple, trigger the crystals and lose to her on the top, she's not called "queen" tho, forgot what she's called

I lost and it was just game over, both on max corruption and 10%. Need to be ready to lay an egg or?

I think ye, and maybe try going there with 100% pregnancy

I think i had done some wrong counting so the 12th ending is actually none. I'll fix it by decreasing the number above it by one.

if you eventually want to make a laying eggs ending, I reccomend to add annother empty nest so that there will be 3 empty nests.

after all, almost all your transformations come in 3. 😜😜

Well, you can add up to three eggs on each nest XD

how do i get the key for the locked door in the donjon

There isn't any key. it was scripted door which can only be unlocked by going in goblin quest.

In the fairy maze with the crystals and plants, the plants break when you go behind them through a warper and they never come back. You can't interact with the crystals again either, making it seem impossible to solve the puzzle without brute force.

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The maze is indeed designed to be solved but not brute forced. But I'll try to take a look regarding this matters.

Help Wanted

I was just getting through the Fairy section, completely unconcerned about corruption (since for some reason nothing was happening to me with the Succubus, Wolf, or Harpia forms), but I barely reached the fairy boss and boom, secret ending... and I saved right where the pink fairy was... I'm in a softlock!


I got this glitch when I'm was testing every form to beat harpy boss. When I enter the harpy boss as a succubus. This appear and when I defeat the harpy boss, it still here.

Thanks for the report!

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What does the mother of slime do? Am I looking for her new born slime?

Yes

It in the dungeon or outside the dungeon that is the town area?

Still inside the first area. One is on the second, third and fourth floor respectively.

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After, i defeated the fairy queen. My character is facing up only, even if I move right, left, down. It will still facing up.

Side note: It got fix when i was reading a sign in harpy mountain

i cant change back after completing the mermaid area

It is known bug. It'll be fixed in the next update.

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Keep getting this bug like three time already. That entire game sceen freeze. And pls send the sceenshot of the menu  because i forgot where is the save button is locate at.

How do i get my corruption to go down? the dispel potion is not working.

(1 edit)

You can't. If the corruption level is maxed out (100), dispel potion will no longer working.

Good game but I'm having a bug right now, After the Fairy queen fight my character is stuck facing upwards and I cannot interact with certain objects, reloading saves and relaunching doesn't work. the only fix I've found is to load a save from BEFORE the fight but the bug just reoccurs.

Thanks for the report!

i also have this issue

Can I get my save from the old version to the new version or is impossible?

You still can play most of it, albeit there might be some bug still linger in the safe files. The good choice is to start a new save, but it's okay if you want to try it.

Alr, thx. Is there any other way to get more magical stone than killing wizard/mage and chest?

Magical stone? Did you mean magic water? The one who replenish mana? You should be able to buy it in the village's shop.

LIke the one get new magic spell

Ah, the tome. Yes, the only way to get it is by gaining it from chests or defeating wizard. 

New Patreon supporter since the  V0.2.3 drop. First off, love the project, it's coming along great. I wanted to give a tip on a game-killing bug. For my save, the Mermaid form is permanent, and the seal in the base has no effect. Not even the transformation effect triggers; just nothing happens.

Went straight for the coast (since the Mermaid content is why I'm here), got my butt kicked and successfully escaped, but not without a tail. Might be related, but my tests haven't yielded any other results. Just cannot turn back at that point. Additionally, once I reached Level 10 in the mermaid form, the breath gauge malfunctioned, allowing me to replenish breath in water beyond the 100 limit. Went afk in the water without realizing, and now I have over 6000 breath.

Like I said, I love the project and it's a blast. Just wanted to give a heads up if it's not already a known issue. Hopefully, there will be more Mermaid-related content in the future? (Wink)

Thanks for the report, the mermaid area and mermaid form is the newest content so far so there'll be indeed some bug regarding it. This bugs isn't acknowledge before, so I'm glad someone manage to find it. And regarding mermaid-related content, yeah, there will be, as the story itself suggested in-game 😉

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My wolf corruption is max everytime if I go outside the base. I will get the wolf corruption cutscene. 

It's already fixed in the new version. Thanks for the report.

is there any guide or walkthrough, I want to know where to go and where the endings are at

Im looking for one too. Is there somethin on patreon?

There aren't any yet. But you can just tell me what ending you already achieve then I'll tell the rest. I might also create some guide at some point.

thank you

Is the wolf corruption bug because I drank a disspell potion and the corruption didn't go down and I can't go up here is block.

Yeah, the current version has bug at the specific spot you mentioned. It will be fixed in the next version.

Surprisingly polished and quality game. But, I can't in good conscience recommend this game without some assurances or clarity on AI usage in regards to writing. Apologies for the essay in advanced xd.

Also, as a forewarning, I have not yet finished the game, so it's possible I'm missing some context that would change what I'm about to say.

Positive Remarks

Really fond of the writing. These types of games usually have god awful dialogue that takes you out of the story, so this was a breath of fresh air. At least from a line to line, diction perspective, it was competently executed. However, some of the promised narrative beats on the page description are absent, which I'll elaborate more on that later.

The combat/gameplay is also a standout in my opinion. Usually with these types of games, the gameplay loop gets monotonous after a while. But because you'll be changing form's regularly, combat avoids feeling too repetitive or plodding, as you juggle different playstyles depending on your transformation. It absolutely adds longevity to the combat. It could definitely be fleshed out more, but for a one person operation, I'm blown away at how engaging and fun it feels.

I also want to touch on the visuals. There's only so much you can do with Kisekae and RPG Maker sprites, but despite that, I think you made the best out of them. The environments are nice and intuitive to navigate, and it felt pretty cohesive still. The moment at the river is prime example of this, and I'd love to see more like that.

Bugs and Suggestions

With my glowing recommendation done, I'd like to note some bugs and suggestions.

  • In Area 1, you can use the dispel potion in places you probably shouldn't (mainly, when doing quests, i.e. when in the slime room, or in the goblin room)
  • Similarly using the orbs when in town (you could be a succubus in broad daylight). It's not a big deal, and it's pretty funny, but thought you might want to know.
  • If you return to the Area 1 intersection, you have to interact with the exit to go to the next map, which is different from all other exits AFAIK.
  • When you remove the harpy transformation, you retain your speed increase (which I will happily use until patched)
  • If you transform into a goblin on the same floor as when the quest is supposed to trigger, interacting with the door gives no dialogue prompt, and you have to re-enter the floor to trigger the quest (mechanically I understand why this has to happen, but still a bit awkward. Perhaps interacting with the door triggers a different cutscene if you're on that floor?)
  • After returning from the goblin room and finishing the quest, the cutscene will have two goblin sprites: One still standing in the prior room, and the one we are talking to.
  • The hero's pendant is removed after any transformation. Thus, if you obtain it prior to beating the boss, it's lost forever.

For some suggestions:

  • I cannot tell what the goblin Magical Dust does, nor a lot of the other transformation spells. There's a little indicator saying +Transformation, but nothing ever happens no matter how many times I use it. Perhaps some clarity on valid targets, or indication of progress?
  • It'd be nice if we can cast the transformation spells we have on ourselves. I definitely prefer the Female Adventurer skills to the Male Adventurer one, but going back to die to enemies in Area 1 takes forever. Likewise, to do certain quests you have to have certain forms, so instead of killing yourself, being able to cast the spell on yourself would be nice. I know later on we can get the orbs, but early game, and for the F-Adv form, I'd appreciate it.
  • There's no way to beat the succubus without being transformed, is there? No luck with using bombs every round, and the hero's pendant did nothing to protect me. I think it'd be a cool secret, if you successfully did enough damage, and you could just give the orb early or something.
  • Early game, the most critical spell to learn is Meditation. Perhaps you might want to force your first spell learnt to be that? Or have some scripted event of using the scroll?
  • The harpy levels are the only place that are not quite as intuitive to navigate (because you can fly). Some indication of which parts of the map leads to the next map would be nice.
  • After getting to Area 2, if you return to the entrance in base human form, the PC still just says "I haven't get any loots yet." instead of a more updated message (that the barrier prevents ANYONE from exiting).
  • The goblin quest, It'd be nice to know where the sign's reference starting point is, as otherwise, even though you know which path to take, you don't know where the path starts.

Concerns About AI Usage

I have plenty more I can say, but I think that'll suffice for the time being. But, I am a bit worried about something. As mentioned, the itch io description states that the game includes themes of "identity loss, adaptation, and self-reinvention." But the last of those themes is utterly absent from the game's narrative.

The writing quality also varies wildly. Sometimes you get evocative descriptions like the screenshots on the store page, but sometimes you get "I haven't get any loots yet." It gives me the impression that, either you at least two different writers, or... AI was used. Especially with how incongruous the game description is to the actual content.

"Expect to change often—and unexpectedly."

This would be really cool, if there were random events that, depending on your actions, can transform you. Not present in the game.

"triggering powerful skills, passive effects, or even further transformations as they fill."

Similarly, it would add a really interesting tactical layer if this were true. Not present in the game (per the content I have seen so far, Succubus, Wolf, and Harpy).

"themes of identity loss, adaptation, and self-reinvention."

Not all games need a meaningful theme. This game is strong enough to stand without one. But, I'd love it if this one did. Yet the in regards to "adaptation" and "self-reinvention", there really isn't much content at all. Certainly no strong thematic throughline of the story.

These features don't need to be in the game to be a good game. And they aren't in the game. So, unless AI was used to write the page description, why does the description state they are in the game? And if AI was used for the page description, how do we know AI wasn't used for the rest of the game's dialogue as well?

Concluding Remarks

I'm not completely against the use of AI in any circumstances. If it's just a passion project, or if the writer isn't a native English speaker, I think it's understandable. In fact, if that were the case, I wouldn't mind helping with the writing! But, I think honesty is really important if you're going to use AI tools, especially so if AI generated material ends up in the game.

I really liked this game. I created an itch.io account just to write this review. But as I was writing it, it became more and more suspect that AI was used in this. So, I'm really hoping for some explanation, or clarification for what I observed. Because I really want to like this game, and I'd even be happy to contribute, but I simply can't, if I believe AI use is being concealed.

Anyhow, that's my two cents. I mean the best, and I really apologize if I come off as hostile or condescending. I just had a lot of fun playing the game, and hope that you'll continue development ethically and honestly.

(1 edit) (+1)

That's... Really thorough review and I'm honestly grateful for this. I can't answer all of it in this reply but you can just reach me in my discord server if you want for further specific answer (The link is on the page.)

As for the main question about if the Game use an AI or not. I suppose I'll just be honest that the writing is indeed use an AI tools, but not at what you expected as the story itself is written by AI. English is indeed not my mother language, but at least I know how to speak with it. I only use the tools for paraphrasing the text that I thought have poor grammar. So, thinks of it just like when someone are using grammarly. All of the story elements, on the other hand, is purely written by me. As for some element that missing for the page description, yeah, it's indeed not there yet. It is on the plan tho, but for some reason, some of it such as the gauge cases didn't work quite as I expected so I decided to rework the bar just as it does right now. I'll try to refine it sooner or later.


As for some other questions that I can answer right here:

- Magical Dust can only work to human or goblin enemies. It'll trigger their Transformation to goblin girl, the difference between magical dust and goblin girl Transformation spell is that the magical dust will also enhance their arousals too. And the other Transformation spell so far is only works for human enemies. 

- As for the goblin girl's quest branching path, it was in the goblin room, especially when the MC trying pass the trap to get an item that the goblin are looking for. When you trigger the trap much enough, you'll get the submissive route, but if you manage to pass the trap, you'll get the corruption route.

- As for the pendant, yes, the Hero Quest is designed to be one time quest per run, so if you miss it once, like transformed or restoring back, you'll also lost all way to progress the quest, as much as losing the pendant.

- As for the other bugs and suggestions, I'm grateful that you write a thorough review and I'll make sure to fix and consider it :D

As mentioned, I think non native English speakers using AI to write is one of the few acceptable use cases. A disclaimer on the site description would be nice, but you acknowledging it is already good enough for me.

Like I said before, I had a blast playing the game, so I really appreciate the honesty. Looking forward to the next update, and keep up the good work! :)

It would also be good to have various different reactions for the dispel potion not working, not only for the older four transformations.

And having more FemMC content would be fun

Like someone else said I'm softlocked too in front of the fairy queen fight because I have max corruption, didn't know there was going to be a double fight. Really good game though imo

(+1)

Already fixed in the current version.

I love this game and played it when it's first released and await a update patiently everytime! Thank you.

(+1)

Glad you liked it!

(1 edit)

what do I do after getting the orbs

That's the end of the content for now.

Fun game. I wish I would have been warned about the double fight in fairy's dungeon. I soft locked my save because I wasn't prepared. Had to begin a new game.

Should've fixed by now, sorry for the inconveniences.

Can you nerf the fairy queen or let me use items before fighting her? I can't even attack her. It's an infinite loo

No worries! I'll do it in the next update!

Will there be an Android/apk Version at some Point?

(1 edit)

I didn't plan to... But you should be able to play just fine via Joiplay in Android.

I've downloaded it successfully, but do you know how to beat the succubus or open the door in third floor? I have no clue

(1 edit)

You need bomb for it! And for the door, you should be in the goblin girl form to trigger the event.

(+1)

Are you developing the mobile version? I don't have any of these devices expect the phon

I don't have any plans to create the mobile version, but you can play the windows version in your phone by using Joiplay. As far as I test it, it's working properly.

Thanks

Hey I'm softlocked bc I saved between the Fairy squad fight and the queen fight (I went to fairy forest right after the town bc it was the only POI I noticed and im level 10/11) and I dont have enough health/defense after the previous fight to survive after my first turn. I might be able to win if Fairy dust puts every stunned/asleep but bc of the dialogue system being so slow I dont wanna keep trying for something so unlikely.

(btw it might be helpful to mention at some point that you can save in the menu) 

(-1)

omg same i actually forgot to save a second save file so im having to start over

it sucks

There'll be a free space in between in the next update, as well as some free turn cost item which you can use without costing any turn.

I tried downloading it on a mac, but when I tried to open it, it said how "The application “Game” can’t be opened." Am I missing something?

I... Can't say for sure since I didn't have the devices to tested it.

(1 edit)

i don't find the third baby slime is it a bug ? ... do you have any advice ?

Try to looking at the upper side of second floor, upper right side at the third floor, and upper left side at the fourth floor.

i tried but i didn't find the third one and when i talk to the mother slime she tell me if i have found a of her children's... then the dialogue stops 

I was scrolling through the comments and saw this reply post from druski789 and I agree. The Idea of A corrupted storyline where the protag is not entirely gone at max corruption, due to being special according to Lilith, would be awesome; but that is up to the dev

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