Sekido is a tall young man with a lean muscular build, and narrow, deep red eyes that have the kanji of "Upper Rank" and daiji of "Four" 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 noticably shrivled and discolored reddish-purple forehead and markings under his eyes that give his face a cracked appearance. He also has the kanji for "anger" etched into his tongue. As a demon, Sekido has pointed ears and sharp nails on each finger. He is usually seen wearing an irritated or enraged expression on his face.