Zatch Bell / Gash Bell / Konjiki no Gash Bell

There are two worlds, Human World and Mamodo World (Demon Kids World). These worlds ruled by laws so it needs a king, to decide who will be king, 100 demon children were sent to Human World with a book for each children to fight each other. The Mamodo have powerful powers but to unleash their power they need a human to become their master so they are can read the spells on their book. A boy named Takamine Kiyomaro was given a little demon named Gash Bell to take care of and help him to achieve his goal. The series has 150 episodes and 2 movies, it has action and comedy, I recommend this for teens to watch.