Phoenix Wing: Rettenjō (鳳翼・烈天上 Hōyoku: Rettenjō, Phoenix Wing: Violent Heavens Above, localized as Phoenix: Rettenjō) is an Arch-Enemy Event Weapon with the shape of a giant 55-inch nail. It is in possession of Bang Shishigami, and previously of Tenjō Amanohokosaka and Trinity Glassfille.
Rettenjō has ability of severing ties with the Boundary. It was developed in secret by Nine, as the core of Kushinada's Lynchpin, which has the ability to stop the functionality of Magic Element, resulting in the rendered uselessness of Magic Formula. It is also the Anti-Event Weapon with power to destroy other Event Weapons.
During the Great Dark War, Nine gave Trinity Rettenjō in secret. However, after they were killed by Yūki Terumi, Rettenjō's whereabouts became unknown, and it was believed to have been lost after the Great Dark War. It ended up in Tenjō Amanohokosaka's possession. Before Tenjō's untimely demise at the hands of Jin Kisaragi, she gave Rettenjō to Bang Shishigami, who was unaware of its power.