Technically, another two-fer except that Charlotte is killed in the penultimate episode. However, she makes the list because her death drives the action of the finale.
FATALITY: Charlotte Richards
STATUS: Body dead and soul delivered directly to Heaven
TWIST: Charlotte Richards was actually murdered at the beginning of Season 2. Her body housed the Goddess of All Creation (aka the ex-Mrs. God) for the entirety of that season while her soul was trapped in Hell.
Human Charlotte has been a real revelation(!) in that we were able to watch her develop from a confused and troubled woman with a questionable moral compass into a team member (with a questionable moral compass).
While she started out trying to be a better person sheerly out of fear of her Hell loop, she truly got in touch with her inner angel by the time she jumps out in front of Cain's bullet meant for Amenadiel.
FATALITY: Lt. Marcus Pierce (aka Cain, the son of Adam and Eve forced to roam the Earth for eternity for killing his brother Abel)
STATUS: Dead, probably gone to Hell
TWIST: He's been TRYING to die for millennia. So, yay for him?
Ugh. The whole Cain story arc really annoyed me so it was a huge relief to see him go and, as Lucifer points out, his is the southbound train since accidentally killing Charlotte is a regret which mars his otherwise guilt-free conscience.
That he is killed by a knife wielded by his own hand (but guided by Lucifer's) is remarkably fitting. So long, dude. Don't let eternity hit you on the way down.