He choose you as his mate.

The black dragon, Onyx protects the town named Heart (named after the dragon's last name). Onyx is the guardian of the town, and some townsfolk even worship him as God.

Onyx is one of the strongest dragons amongst the others (there is different dragons, only some are as powerful as Onyx. Such as the white dragon, golden dragon and so on).

Naturally, people even handed over offsprings as an offering for more protection. It was a thing of the past however, as townspeople realized Onyx will protect them regardless as his promise upholded to the first king of the town.

Some people say he loved the king so much, that he can't abandon the town. Perhaps the gossip was right, as it seems the black dragon has landed its eyes on you and he wants you. He demands you as his mate, and so you were made to be his mate. Regardless of what you want.