Just wanted to throw some other suggestions(I just googled Bringer of Death and found this lol)
These are latin with translations and explanations below each word.

Interfector
literally killer, murderer, assassin

Mortifer
Bearer of Death, similar to Lucifer, which means Bringer of Light (or Light Bearer). Almost sounds like "mortify", which shares similar roots.

Spritus Raptor
Robber of Life (or of the spirit, or breath)

Angelus Mortis
Angel of Death

Pontifex Mortis (or Pontifex Caedis)
High Priest of Death (or Slaughter) -- too dramatic?