Koenma Daioh is a prominent supporting character in the anime series Yu Yu Hakusho. He is the son of King Enma, ruler of the Spirit World (Reikai), and serves as its junior administrator. Often appearing as a toddler with a pacifier, Koenma oversees the judgment of souls and works closely with the series' protagonist, Yusuke Urameshi. Despite his youthful appearance, Koenma is intelligent, responsible, and occasionally takes on a more mature form when the situation demands. He plays a crucial role in guiding the main characters through various supernatural challenges.