Tsubasa Kurenai is one of Ukyo's many suitors—and like most of them, he's a cross-dresser despite his convincingly feminine appearance. He originally met Ukyo back when they both attended an all-boys school (she was disguised as a boy at the time). He fell hard for her almost immediately and basically buried her in love letters and gifts, but she wasn't interested. Even after she left to chase down Ranma, Tsubasa kept writing. Ukyo eventually sent him a letter explaining the engagement and included a picture of Ranma's female form to really drive the point home—which, somehow, didn't stop him either.
He eventually got Ukyo to let him help deliver okonomiyaki from her restaurant, mostly because she knew she wouldn't have to pay him much. That's when things got weird. Maomolin, who works part-time at Shampoo's Cat Café, took one look at Tsubasa and decided he was the one. Now Maomolin constantly chases him around trying to convince him to be his bride, which Tsubasa absolutely does not enjoy. Even after Tsubasa explicitly told him he's actually male, Maomolin just shrugged and said nobody's perfect, so the chase continues.
Tsubasa's also known for his ridiculous disguises. He'll dress up as basically anything—a tree, a mailbox, a trash can, a vending machine, a washing machine, Ucchan's sign—sometimes during fights, sometimes seemingly just to make a dramatic entrance for no reason at all.
Content compiled by AnimeList.moe from publicly available sources.