Voice actor just nailed it + the writing of the guy who made HAWP which is basically fairly random humour is natural fit. Lots of silly oneliners just like when you kill COV in BL3.
Killing yourself because your dumb a** melee skill kept proccing self damage repeatedly.
Throwing axes that also happen to explode.
Hillariously implemented suicide bombing mechanic.
Also Krieg is the german word for “war” which certainly helps sell the character.