Donovan is an Iron Warriors Chaos Dreadnought that has in several hilarious threads on /tg/, claimed to be Tankred's rival, despite the fact that he's kind of out of Tankred's league. Like Tankred, he appears to be in it for the bitches and booze, but claims to be superior, because everyone knows Chaos chicks put out. Battles with Tankred have usually resulted in the two ineffectually screaming and throwing Plasma Cannon fire at one another until Donovan, inevitably, suffers a Crazed roll and winds up firing on his own troops or trying to rush into close combat, ergo leading Tankred to enjoy victory by default - every single time.
Tankred can only smile at his antics. The crazy fuck cracks him up.