[Slydria]

Well, here's an idea on how I think it could work.

Enma's Summons
Applies a debuff 'Deathbound' to all enemies that will incapacitate them the moment they fall under a certain HP threshold equal to LV% of their Maximum HP. (LV is based on Rank), this lasts for 5 Rounds.

If an opponent is incapacitated by this effect, they are removed from the battle. Effects that would stop this from occuring do not apply (Last Chance, From the Ashes, etc.) and they cannot be revived since they are no longer apart of the battle (see: Die Hard, Sal Violates, Second Chance, etc.)

Rank 1: 50FP, LV: 10
Rank 2: 47FP, LV: 13
Rank 3: 44FP, LV: 16
Rank 4: 41FP, LV: 19
Rank 5: 38FP, LV: 22

(Rank 6: 35FP, LV: 25)