F Rank? I Got a God-Tier System!

Dimensional beasts have broken into the world, and what a person can do about them depends on the rank they awaken at, F at the bottom and S at the top. He awakens at F. His girlfriend, who has an S-rank weapon spirit, leaves him for someone stronger. He is about to be killed in a beast attack when an evolution system awakens in him. It lets him hold contracts with more than one partner at a time, and it lets him spend points to raise the rank of anyone he is contracted to and wake abilities they have not reached on their own. He contracts a weapon spirit, a succubus, an azure wolf girl and an angel, and builds them up past what their own talent allowed. With them he fights the beasts, and he comes back around to the people who had written him off when he was F-rank.