[Rendar]

If an enemy is killed by start of round effects such as SEAR, POISON, or BURN, they are still 'alive' come start of the round. Causing your spells to hit them, and possibly lose a momentum due to them being resistant. They disappear right after you spend any momentum, however.

[LadyLightning]

They can also be targeted with Life Drain while on the field with 0 HP,
enabling one final little dose of lifesteal at the end of a battle. It also
happens when an enemy dies to Ingrain's life leech.