Phenex (フェニクス, Fenikusu) is one of Kouen Ren's three Djinn and the Djinn of Kindness and Mediation. Phenex was in the 37th Dungeon. She is a Djinn who uses the 8th type of Magic, Life Magic. She was part of the Garuda tribe in Alma Torran.
Phenex is in the form of a woman that carries a trace of sorrow about her. She has bird-like feathers. She has long, feathery hair and pointed ears. A large and very ornate headdress resembling the sun frames her face, and she is also adorned with several necklaces. Aside from her jewellery, Phenex is nude.
Aladdin wants Kouen Ren to send back his soldiers, but since he doesn't seem to believe him, the Magi summons Kouen's three Djinn. Phenex, along with Agares and Astaroth, appears saying We are here to serve you, our "King" and the reincarnation of our past "Great King".
Immediately afterwards, Aladdin also summons Amon and Leraje, and all the Djinn ask to Aladdin if he called them. Amon explains the situation while the other Djinn listen. When Kouen understands that Aladdin knows all of the history he wants to know, grabs the Magi and orders him, with a scary expression, to tell him everything. Phenex, Agares and Astaroth are horrified by this, and beg their King to stop being so rude toward the Magi. Aladdin accepts telling everything to Kouen if he helps to destroy the Medium, and all the five Djinn are incredulous by that. While all the Dungeon Capturers Equips, the Djinn say that they leave everything to them, their King Vessels.
Kouen Ren is Phenex's Dungeon Capturer. As a Djinn, she can alter her size and rule her Dungeon. After she was conquered her Healing Magic are being used by Kouen. Phenex's Metal Vessel is the hilt ornament on Kouen's sword. The only known member of Phenex's Household is Kin Gaku.
- Ring of Admonition (いましめの輪, Imashime no Wa): Using Phenex's power Kouen puts inside the target's body an egg that is warmed by the target's bloodlust. In the moment the enemy has concrete intention and confidence, the egg cracks to create a magic ring around his head and isolate bloodlust from his body. If the target is trying to move while the nerves are being sealed, the curse may leave him in agony.
- Her name is probably taken from the book The Lesser Key of Solomon. In the first section of this book, entitled Ars Goetia, several demons are described, Phenex being the thirty-seventh. The dungeon where Phenex resided was the 37th as well.
- Phenex's bird-like qualities may come from the fact that her name sounds a lot like that of the mythical bird phoenix.
- Phenex is originally a Garuda that, according to the Hindu mythology, is a divinity depicted as man-like creatures with wings, large enough to block the sun.