UnderBattles - AU Fights

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1.17K reviews
Content rating
Everyone
100K+
Downloads
Content rating
Everyone
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About this game


This is a completely free to play fan-made unofficial project based on the original Undertale™ game created by Toby Fox.
All rights, characters, and assets belong to their respective owners.
This game is a fan work that is not affiliated with Toby Fox or the official Undertale team.
For any copyright inquiries or asset removal requests, please contact me directly at kywoo0130@gmail.com. I respect intellectual property and am fully committed to resolving the issues!

There are many battles from different Undertale universes that were made by KYwoo and many other creators.
We can kind of say this game is collection of Undertale fangames!
Have fun everyone!!
A game that includes many kind of Undertale fangames from many AUs!
Updated on
Jul 18, 2026
Available on
Android, Windows

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • No data collected
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  • Data is encrypted in transit
  • Data can’t be deleted

Ratings and reviews

1.08K reviews
Kandra
November 11, 2025
It's a super cool game, one of the best Undertale fan apps I have ever played. Some issues I had were the controls not moving where they were supposed to. I put that I wanted them on the right side of the screen, but it ended up on the left anyway, plus it wouldn't let me move it to the other side in the customization menu. That's really the only problem I had. I can't wait for another update and more battles! Maybe we will get OG Swaptale Papyrus or a normal Sans fight.
12 people found this review helpful
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KYwoo
November 18, 2025
Thanks so much for the support! I will do my best to improve the gameplay and adding new battles within the next updates.
Elias Klinger
March 15, 2026
It is nice, but I do have a few suggestions. First it would be nice to have the ability to change the main menu theme and song, same with the battles. Also, can you add Forced Smile but remade, because the original one is incomplete? Anyways, this game is still really good.
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Ky Kitties4Friendship
December 30, 2025
The battles are pretty good, but they are extremely difficult to maneuver. And I like that the naming works the same as UnderTale, like with Chara being the true name, and other characters' names not being allowed. HOWEVER! Gaster crashing the game is completely understandable (as it does that in UnderTale & Deltarune), but River also crashes it!! IDK if it's a bug, a glitch or just some AU's rule, but please get rid of it. Thank you.
1 person found this review helpful
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KYwoo
November 28, 2025
Hi! Thanks for giving feedback, the battles might be difficult but in the future basic mode will be added. Please keep in mind that this game is only mobile game that actively developed, so i would appreciate your support!

What’s new

UnderBattlest REMASTERED - Will be released at 2026-2027!