 If you liked
D.Gray-man
|
 ...then you might like
No.6
|
Though the stories in themselves aren't really similar, the main characters cross over nicely.
Allen Walker is like Shion with the scar on the same side of his face, brown hair which turned white after a near death experience, and his happy, innocent demeanor despite what he's been though.
Kanda Yu is similar to Nezumi with his bluish-black hair always worn in a ponytail (though longer), his irritation at how naive the main character is, his exceptional ability to fight, and his unknown origins.