Well, I'm guessing since you are here, you probably know what needs to be known. If not, I'll give you some info. ^__^
Naoe Nagi is 15 years old, and the youngest member of the assassin group, Schwarz, in Weiß Kreuz. His slightly older form, but still youngest member of Schwarz also appears in Weiß Kreuz Glühen. Physically, he is quite weak, but he has awesome telekenetic powers, earning him the code name, "Prodigy". He is also a genius, a whiz with computers, and is often put against the youngest Weiß assassin, Omi, both in combat, and in any computer related fight, such as stopping Omi from hacking into something.
Long story short, the kid is awesome, and sexy. Love him. Love him, I say :D