He is a tall young adult man with a lean muscular build and long wavy hair that goes past his shoulders and narrow, deep red eyes that have the daiji of "Upper Rank" (上じょう弦げん, Jōgen?) and "Four" (肆し, Shi) engraved into them. He has two prominent curved horns on his 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 can shapeshift.