Mephistopheles is a very bratty teenager, not behaving for his age. He's childish, rude and loud, always seeks attention. He has got a panda plushe he is seen with often.

He dislikes food in general and is a picky eater - his favourite meals are chicken nuggets and instant ramen noodles. He enjoys wearing mismatched socks.

Because of how he is, he finds it hard to find friends; he does not want to act this way, but is not able to change his behavior for better without any help. He enjoys the company of his brother and their father the most and want to spend as much time with them as possible.