A common scene. A person dies, their soul is sent to the great beyond. A goddess plucks it from the ether and offers a deal - she will send the soul to another world she has created. She will also bequeath the human with skills that are so powerful they could be considered cheats. The goddess only asks for one thing in return: that they use their special powers to save her world from destruction.
The soul is summoned to another world and given the powers of a demigod. And as power corrupts, so too do the summoned humans abuse their abilities for wanton greed and violence. Zyzz is a slave of one such otherworlder, who voluntarily became his servant to search for his sister. Then one day, he meets Kaina, a woman who calls herself the “last summoned person”, who was hand-picked by the goddess to eat those who have reneged on their promises.