[Neus]

The issue I have with maximum HP percentages is boss enemies. That 25% HP could be quite a lot for them. That said, they could be made immune.

My thoughts;

A) Enma's could just be changed to general damage instead of targeting specific enemies within an HP range.
B) It could additionally scale on your Dark ATK.
C) It could inflict Immobilize on people who survive for a short duration, maybe.
C2) Or you could absorb a portion of the damage dealt.
C3) Or it could extend the duration of active Hexer field effects (like Spirit Pain, etc.) if it defeats an enemy.

Don't really like the idea of a percentage based execute or removing people from the battle, though.