Aizetsu

takes the form of a rather tall young adult male with a muscular build, long wavy hair and narrow eyes with kanji "Highest Rank"(上じょう弦げん, Jōgen?) and "Four"(肆し, Shi?) engraved on them. He has two curved horns on his forehead and cracked markings under his eyes. Aizetsu also has the kanji "sadness" engraved on his tongue. Aizetsu has pointed ears and sharp claws on each finger. He can usually be seen with a dejected expression on his face. Aizetsu wears a black kimono with white lines running through its various parts and accessories similar to ropes tied around his shoulders. He also wears hakama pants and a pair of dawns. Aizetsu can always be seen with Jumonji-yari (十じゅう文文んん, Jumonji-yari?).

As the personification of Hantengu's sadness, Aizetsu is portrayed as completely dejected, sullen and negative, as he constantly described everything as depressing. Of all the clones of emotions, Aizetsu turned out to be the most calm and collected of all five, as can be seen from the fact that instead of frivolously wasting time on "entertainment" like Urogi and Karaku, or immediately getting worried and angry at something like Sekido, Aizetsu calmly analyzes his opponents, thinks over his strategy and finds out the strengths and weaknesses of his opponents before attacking.