Almost every native English speaker knows the meaning of morte. We have a words like mortician which is a person who cares for the dead, mortgage which is a plan to kill you debt, rigor mortis which is the stiffness of death and mortal which means subject to death. Yes, we almost all know what morte means. That is why it was the name given to a talking skull in a game. Just like love and hate, however, we often use native words in English for our most basic concepts. Death is one of those.
You also have Mallory's "Le Morte d'Arthur" (no talking skull involved in this one). That said, it was just a small nod to Gabriel's appreciation of the game, which after so many years I still consider the best RPG ever made.