Monster Eater

Nobody wants "Grubby Forager" Rudd on their adventuring team. His nickname—and his stench—come from his constant treks into the Noxious Labyrinth to gather medicinal herbs, a job he survives only thanks to his status immunity skill. When he's finally recruited as a party porter, things seem to be looking up… Until a deadly dungeon monster appears and his fake allies use him as bait before abandoning him! Wounded, destitute, and barely surviving the attack, Rudd breaks a forbidden taboo to stay alive: eating monsters. But the more he devours, the more power he gains, kicking off a thrilling, adventurous gourmet fantasy!

(Source: Square Enix)
Mamonogurai no Boukensha: Ore dake Mamono wo Kuratte Tsuyoku Naru