A newer Karakuridoji created by Dr. Dunstan, and is Ultimo and Vice's 'little brother'.
The representative of envy and jealousy (hence his name), Jealousy was the karakuridouji of Iruma Tomomitsu (whose past self was also his master back in the 12th century), until he was killed by Jealousy himself, after deeming that Iruma wasn't helping him learn about good and evil (stating that 'his evil is too shallow'). Eventually, Yamato's best friend Koidara Rune becomes his new master, much to the suprise of Yamato and Ultimo.
He is first seen after Yamato meets the Good Douji Club, watching Rune trying to find Yamato to warn him that someone is hiding the existance of the Karakuridouji. He later confronts Rune, questioning him of his past life in which Rune was actually a woman named Lady Gekko, who was romatically involved with Yamato's past self. He becomes Rune's karakuridouji by arousing the hidden anger inside him. This anger is caused by his jealousy over Yamato loving Sayama, despite the fact that in the current life he is a boy and is no longer romatically involved with Yamato, nor is Yamato aware that Rune is in fact, Lady Gekko.