I'm not sure where to start in talking about Sanada because this could easily turn into a very long essay detailing why exactly Sanada Genichirou is one of the best things since sliced bread.
But for basics, he is the fukubuchou of the formidable Rikkaidai Fuzoku Chuu. A team that has won the national championship for the past two years. Sanada is said by many to be the best junior player in Japan. He's tall, dark, handsome, and just a little violent.
Needless to say, he's much more than that, and I simply adore him.