Kenyuu Horiuchi (Japanese)
Stolas (ストラス Sutorasu) known by the public in Seiji's hometown as "Stolas the Demon". A sociopathic anthropomorphic penguin with violent tendencies, Stolas bears a disturbing obsession with Seiji's younger sister Akua. He attacked the two as children but was locked in a cage until he broke out years later to chase down Akua once more. Stolas doesn't necessarily speak per-se, it's just implied that based off Stolas' eyes what he may be saying.