After stopping the highbreed invasion and saving their race, stopping Vilgax and using Brainstorm to regain master control, his old transformations and a few other forms Ben's life has been relatively peaceful. More than he was comfortable with, so to gain some interest in his life once more Ben's parents suggested to live with his older cousin Saki Sato in Japan. Mainly because the school Saki will be working at will have semi human students. Demi humans being people with unique characteristics that inspired motifs in history. Examples being Vampires, Dullahans and succubi. Now Ben 10 is friends with a hyperactive cheerful vampire, a modest kind Dullahan and a timid manga fanatic Snow Woman. Oh and remember his aunt Saki Sato? Turns out she's also a Demi human, specifically... a succubus... One of Humatrix's many challenges