This is the first Usagi TPB. It collects the stories that pre-date the first Usagi Yojimbo ongoing series.

A BATTLE FOR THE AGES! The gods did not bless Groo with brains, only with the ability to battle. Now, they themselves are in conflict over the spirit and future of mankind . . . and it is Groo who becomes the pawn (unwitting, of course) in their war. If the future of humanity depends on the wanderer—we're all in a lot of trouble. It's the basis

Duke "Destroyer" Duck, a resident of the anthropomorphic world, is in a brutal rampage against a ruthless company from another dimension that exploited and killed his only friend. Issue also has the first comic book Groo Wanderer.