Ansem the Seeker of Darkness (Xehanort's Heartless), is a short Brown cloaked Heartless. That's what he originally looked like as a Heartless.
Later by the end of KH1, Ansem SoD possessed Riku and later kicked Riku's heart out.
After kicking Riku's heart out of Riku's body, Ansem SoD later...