Duck heart - Joann Sfar

Welcome to Dungeon, the looniest world of horror and heroic fantasy you'll ever be transported into! This series, a bestseller in many countries, starts with the apogee of Dungeon, a might castle filled with monsters, trolls and goblins kept by a wily bird, the Dungeon Keeper. It is now about to be attacked by an army of tentacled soul-eaters! To defend the Dungeon, Herbert the Timorous Duck is told to retrieve a fearsome barbarian, only to see him being beheaded. Without the slightest notion of what he is getting himself in for, Herbert mocks himself up as the barbarian...