Crossover Mythology: Chang Xi's Style Is All Wrong

For Changxi (male), the following things were true throughout his thousands of years of life. He was a human from the Land of Xihe. He had an older sister named Xihe, the Demon Emperor Dijun was his brother-in-law, and Wangshu, the Star Lord of the Lunar Star, was his and his sister's master. When his beautiful sister married the Demon Emperor Dijun, he was so happy that he drank a little too much and dreamed of Changxi (female), from another world after the War Between the Lich Tribes. Changxi felt his mind shatter. Who the hell is a girl?! Changxi (male): So, my sister and I were supposed to be the Star Lords of the Lunar Star. Our master doesn't exist, I was supposed to marry Donghuang Taiyi, and in the end I eloped with Hou Yi, a member of the Witch Tribe, becoming Chang'e and spending the rest of my life in the Moon Palace with only the moon rabbit and Wu Gang for company! And also, I'm a woman... What the hell is all this?! The War Between the Lich Tribes is inevitable. The ten Golden Crows will die, and my sister and brother-in-law will meet a tragic end... Changxi was miserable: I start off with a hard-mode dungeon. Is that really fair?! Hey, Taiyi over there, listen up. If anyone's marrying anyone, I'll be the one marrying you! The pairing is, of course, Taiyi. No explicit content. Either the male lead tops, or they switch.