Tetchu Suehiro is apart of the Hunting Dogs and first appears in the Bungou Stray Dogs manga during the Decay of Angels arc. Although his ability rather unknown, we do know that his ability "Plum Blossoms in The Snow" can change the size and shape of his sword and is said to be the strongest ability in the Hunting Dogs. He is on the more stoic side and takes his job very seriously. (Source: Bungou Stray Dogs Wiki)