I'm pretty sure that's either Taka or Tamahome 
from FY. The eyes are too big to be Tasuki's, as 
his pupils are usually really small. The way the 
hair is drawn also makes it look more like him. I 
wish I could find the exact scene it is, but you 
can see how much it resembles Taka/Tamahome's 
design at Lil' Otaku Shinobu's Gallery, located 
here.

-Ryouko