Blizzard Entertainment revealed the Diablo III: Reaper of Souls expansion trailer at GamesCom during a press event held at 11:30am CEST.
The Crusader is a new mid-range class wielding a longsword and a shield -- based on the Paladin.
The Archangel of Wisdom: Malthael, plays a big role in the story as a villain. He is now the Archangel of Death and sees humanity as the largest group of demons. Thus, he wishes to erradicate the Eternal Conflict by killing both the humans and the demons.
Malthael steals the Black Soulstone from Tyrael and the Horadrim -- who prepared to bury it deep beneath Sanctuary.
Further details of the Diablo III expansion will be revealed at BlizzCon this upcoming November 8-9th.