If you liked the Code Geass: Lelouch of the Rebellion manga, the Anime-Planet community thinks you'd like:
Code Geass and Full Metal Panic! Are about high school aged students that get caught up in a military type of situation. With lots of intense battle scenes and giant robot fights these two series are perfect.
Teenage genius Hiyama is fed up with the world: daily life is boring, and everyone around him is little more than living filth. One day, after a particularly trying day of tolerating the human scum that populates his high school, the boy decides that the only logical solution is to completely destroy the world and all of its useless creatures, then rebuild it as he sees fit. To this end, the teenager starts dabbling in hypnotism, and in a matter of months has half the school and even part of society under his control! However, this violation of free will won’t go unchallenged: another highly skilled hypnotist is determined to outsmart and stop Hiyama. In this dangerous game of cat and mouse, which man has the intellect to outwit and outmaneuver the other?
Both main characters are high-intelligent studants who can control other people's acts and choices, using it in their own intents to make the world a better place. As Schneizel stated in Code Geass, the geass power can be considered a very strong kind of hypnosis - and that's exactly what Ren does in Lost+Brain. Both of them are bored with the world around them (although Lelouch have a real reason to seek for revenge and Ren does not). If you are also a fan of Death Note and all this "genius anti-hero" stuff, you will enjoy Lost+Brain even more.