Jerry would win through dumb technicality. Explanation in comments.

Nah, Xander would win. I don’t care how op how powerful your obscure ass undertale AU is, Xander literally has more weapons, more experience, and better armor.

Read my comment.

I said through DUMB TECHNICALITY. It's meant to be obscure, silly, and not make sense.

Well if it was dumb technicality then Xander would easily win

Did you actually read it

Yes. It’s just one big dumb “reason” why this Undertale AU could “win”

jerry wins tbh

Underfell has a self-defense gimmick where the more damage he takes, the tougher his body gets. So it would eventually reach the point where Xander can't damage him. Similarly, the headband of his makes him stronger as the battle goes on. Therefore he would eventually grow so strong he could one-shot Xander. This means that Xander would be left to die or surrender.

what if he just

forcibly takes off his headband

Still can't change the fact he's invincible

EXACTLY!

Still can't change the fact he's invincible

My brother in Christ: if he’s invincible then why even make this a fight

Cause funni red sword

and besides the murasama is enough to cut through jerry’s fatass in 0.04 seconds

Yep