Konosuba: God's Blessing on This Wonderful World!, Vol. 1 (light novel): Oh! My Useless Goddess!

Game loving shut-in Kazuma Sato's life as a young schoolboy in Japan abruptly comes to an early end...or at least it was supposed to. When he opens his eyes, though, he sees a beautiful goddess that offers him a once in an after-lifetime chance to be reborn in a parallel world. The catch is that the world is violent and threatened by a growing evil! Fortunately, he can choose any one thing to bring with him. So he chooses the goddess, Aqua! And so his adventure with his gorgeous companion begins…