Kuro no Shoukanshi
Kelvin is ready to start a new life in another world. But first, he has to give up some of his memories from his previous life. In exchange, he gets powerful abilities, extra skill points, and an S-class summoner title. As a bonus, the goddess who's helping him out with his reincarnation, Melfina, offers him a companion of his choice to give him a head start.
Kelvin has fallen head over heels for Melfina, so he chooses her without hesitation, believing that even without his memories, his love for her will remain strong. With Melfina as his guide, they begin their journey together.
Kelvin needs to collect a lot of mana points in order to summon Melfina's physical form. So, he must level up by fighting strong enemies and making contracts with even stronger allies. With Melfina by his side, Kelvin is determined to make his dreams come true.