The Neo-Soviet marine biomods
Classified as a category 4 threat, the Elib is somewhere between a vampire lord and Godzilla for limits of escalation. Yes, I would consider using a nuclear device to kill just one. I am that sure that I want it dead.
On some of the islands off the coast, the rites of the local fertility god revolve around ceremonial death and rebirth. The religion's priests have overcome this cycle, however: Each of them is actually undead, ceremonially slain and "reborn"! Their religion is otherwise unremarkable, being an odd offshoot of the mainland's religions. The priests vow to resist their undead cravings, seeing these as the "cycle of life" attempting to reclaim their spirits.