I Made a Contract with Yinglong at the Beginning, but the School Beauty Called Me Master

Lu Xuan traveled to a strange and dangerous world and became a person with superpowers! With a weak constitution, he activated the contract system when he was about to die from the monster's maw of blood! As long as you contract with the ancient beast, you can strengthen yourself! The ancient mythical beast Yinglong is given as a gift at the beginning, which greatly increases Lu Xuan's strength! But the development of things was somewhat unexpected. "I contracted with the ancient Yinglong, how did I become the school beauty?"