Mar Vol 4

MÄR by Nobuyuki Anzai. A Fantasy manga rated Teen, published in English by Viz Media.

Ginta Toramizu is a daydreamer who's bad at sports and school but obsessed with fairy-tale worlds. When he's suddenly transported to MÄR-Heaven, a land of magic, he discovers he's strong there and teams up with Babbo, a sarcastic talking weapon, to face the evil Chess Pieces.