Shirou Yusa (遊佐司狼, Yusa Shirō) Voiced by: Takeshi Maeda[1] (Japanese); Austin Tindle[2] (English) Ren's childhood best friend who is a genius but bored with life. Due to being constant thrill seeker, he has a brutal fight with Ren, breaking their friendship. He then disappears from school and hasn't been heard since.