I recommend two novels," Loser wants to defy the heavens: The black-bellied female mad god " and " The peerless demon concubine: The black-bellied lord, please let go." The female protagonist of " Loser Against the Heavens " had experienced nine calamities and went against the heavens. She became a black-bellied female crazy god and finally climbed to the peak. In " The Peerless Demon Concubine: The Black-bellied Lord, Please Let Me Go," the female protagonist became a good-for-nothing Crown Prince who disguised herself as a man. After experiencing life and death, a powerful beastie army was behind her. The female protagonist and the male protagonist were both black-bellied and powerful characters. They were a pair of strong partners. I hope you like my recommendation.