How did the God of Destruction Become My Pet?

At the beginning of time, something severed the connection between Earth and the other three worlds that once were one. Billions of years later, this connection finally was healed, and the humans of today found themselves fighting off hordes of otherworldly beast which are hellbent on destroying everything. In the wake of this connection, Sigils were born, people who could use an energy called Fey. This energy allowing for humanity to fight back, the only problem being that this power favored women over men. So in a rush to create a way to fight, the Elite Sigil Corps was born. Soba is an average guy who has a slight affinity with Fey, able to draw out the power in Mystical Beast, making contracts and so. But alas, he is mere dirt compared to the women of the Elite Sigil Corps, his older sister even being a renown soldier. However, that would all change when Soba sees his sister lying still, a huge Dragon that can level skyscrapers coming toward her. What will he do, well, what wouldn't he do but run head first at the Dragon in hopes of stopping it.