[Rendar]

If you, somehow, take damage whilst KOd (which seems to be a thing with the new FFA system. AoE attacks and eventmin stuff can harm 0 hp targets)...

It can proc certain effects (I haven't tested Armor of Nails, but it likely still triggers), such as From The Ashes (Phenex) and Last Chance (Ghost) and revive the target because they 'hit' 0 hp.

[Neus]

Being able to damage downed enemies via skills needs those skills reported specifically but revive effects should no longer trigger if you somehow take damage while at 0 HP.