WordNet sense 1 (involving loss of divine grace or spiritual death):

deadly

WordNet sense 2 (not admitting of pardon):

unpardonable

WordNet sense 3 (of earthly origin (as mortals are)):

earthborn

WordNet sense 4 (having or showing no mercy):

merciless, unmerciful

WordNet sense 5 (causing or capable of causing death):

deathly

WordNet sense 6 (bringing death):

fatal

WordNet sense 7 (a human being):

individual, person, somebody, someone, soul