Lykon

Lykon was an immortal and former member of the Old Guard. He is the first immortal known to have died and not regenerated again.

History
Lykon and Andy crossed paths after dreaming of each other for a couple weeks. They met in Judea when Alexander the Great conquered the city and worked together for nearly two millennia.

Death
In the comics, Lykon was killed fighting in a city-state war alongside Andy in Italy during the Rennaissance. In the movies, he is shown fighting in a skirmish alongside Andy and Quynh, then dying from his wounds.