In naruto what is sai first name?

Sai is a traditional weapon. Dagger shaped blackjack-weapon, with two curved prongs projecting from the handle...

Sai could also mean a spy sent by stupid Danzo to look over for team Kakashi's action particularly on Naruto cos he's interested in Kyuubi's power, duh what a lousy old man. But I think Sai had a change of heart already since the guys taught him emotions he haven't felt before, so weird. He's got this seal on his tongue so he could not talk about Danzo thus keeping all his plans secret, oh yeah all of his minions have seals too creepy.