If you're looking for manga similar to Bloody Brat (II), you might like these titles.
Every 666 years, the ruler of the demon world changes. All the children of the former ruler must battle to see who will ascend the throne. To do this, these 'Satans' will team up with the human sorcerer 'Solomons' and fight in pairs. The Solomon of the winning pair is granted one wish. This 4-koma follows the story of one of those Satans, called Aini. Unfortunately, the human who summons Aini is actually just an erotic doujinshi writer who was doodling. He seems really into Aini, and he makes it clear his wish is going to be something (probably perverted) involving her. Their first battle is against another doujinshi writer, a girl who's really into tentacle porn. Since none of the Solomons have any skill with magic, they're going to have to find a different way to battle it out...
Kanan is a demon hiding in a high school in the human world to feed on the souls of humans. She sets her sights on a single high school boy, but somehow ends up in a lovers contract with him!? Kanan, who has never been in love, is now filled with new feelings!