Black Dragon Reborn – Contracted by the School Belle?!

Lillian Frost has no money and is in a bad spot when she summons a small lizard in front of a crowd, and the crowd laughs. The lizard is the Black Dragon King. The two of them make a deal: she helps him get his power back, and he helps her stay alive. Almost as soon as the contract is in place she makes him swallow her necklace, and he has no idea why she wants that. He had just come back from killing a god when someone close to him stabbed him in the back. His soul fled into a dragon egg, and when Lillian's summons pulled him into the human world he came out in the body of a lizard. The first time he tried to breathe fire it fizzled, and people in the crowd asked whether the lizard had hiccups. Then the dungeon runs start. On the hardest difficulty one breath from him burns out everything inside. A boss kneels and begs, and he finishes it with a single slap and takes its power for himself. Dungeon records fall and the people who mocked Lillian go quiet. The ones who pushed him off his throne are still hunting him, and the war between dragons pulls Lillian in along with him. An old enemy of his eventually turns up, and he meets that enemy in a half-dragon form the crowd has never seen.