Sekido is a tall young man with a lean muscular build, and narrow, deep red eyes that have the kanji of "Upper Rank" (上じょう弦げん, Jōgen?) and daiji of "Four" (肆し, Shi?) engraved into them. When he was first formed, he had unkempt wavy hair similar to Hantengu. After Aizetsu forms from his head, he grows long, spiky hair that goes past his shoulders. In both instances his hair had a reddish tinge. He has two prominent curved horns on his forehead and markings under his eyes.