undeadly

As a noun death

is the cessation of life and all associated processes; the end of an organism's existence as an entity independent from its environment and its return to an inert, nonliving state.

As a proper noun Death

is the personification of death, often a skeleton with a scythe, and one of the four horsemen of the apocalypse.

As an adjective undeadly is

not subject to death; immortal.

As an adverb undeadly is

immortally; eternally.