6. Malthael from Diablo 3: Reaper of Souls
Malthael is the titular Reaper of Souls in Diablo’s universe of sanctuary. An avenging angel who decides to destroy all of mankind due to their half-demon lineage, Malthael can only be stopped by the Nephalem. Fighting him makes a lot of the pain and suffering you go through in RoS’s storyline worth your while—and it opens up Adventure Mode, which is a huge plus.