Series like Loveless

Twelve-year old Aoyagi Ritsuka lost his only kin when his brother, Aoyagi Seimei, was killed under mysterious circumstances. One day, he meets Wagatsuma Soubi, who claims to know his brother. It turns out that Soubi and Seimei used to be a fighting pair, whereby Soubi was the "Fighting Machine" and Seimei was the…