Now I wonder, does being in Zombie status protect you from Mega Death?
Yes this is how it works. This fight is super gimmicky if you're not aware how it works because you have to keep one character with zombie status (and somehow keep them alive) so your party isn't wiped by Mega Death. Also even aside from that gimmick it's still one of the more challenging fights even after you know how it works. Probably not as bad as Seymour Flux but this one gives a lot of people trouble also.
Death Ward might also work regardless. I'm not sure about that, but I do know for sure that Zombie status blocks Mega Death. ---
Congratulations to BK_Sheikah00, this year's guru to achieve contest enlightenment!