Ryou Shirogane. I mean, he memorized his father's research journal and went through college at age eight AND found a way to genetically combine humans with animal when he was sixteen.
Ed :) He can figure out the enemies plan so quickly. या make up a counter plan that works out perfectly. Not to mention he learned alchemy and did human transmutation at such a young age!
But sadly this only happens when he puts his mind to it -_- Most of the time he's making up stupid ideas to kill घोड़ा या ranting about people calling him short.
Gukodera and Belphegor from Katekyo Hitman Reborn! (KHR!)
Gukodera is smart and has a hot temper... :) Bel (Belphegor) is actually a genius even if he is childish and...often doesn't दिखाना he is a genius...well, he is a hitman and a prince (he really is a prince..) and he has sadism... :)
Belphegor has blonde hair and Gokudera has silver/white hair