Based on data from the OZ-00MS Tallgeese and the other Gundams, the Gundam Epyon was created by Treize Khushrenada while he was placed under confinement by the Romefeller Foundation. In keeping with Treize's philosophy, the Epyon eschews cowardly long-range weapons in favor of chivalrous close combat. However, when the suit becomes a part of White Fang, a pair of Vulcan guns are added to the head. Its main weapons are a segmented, whip-like heat rod mounted on a shield and a powerful beam sword whose energy is supplied by a direct connection to the Epyon's generator.
Gundam Epyon EW is Hajime Katoki's redesign of Epyon in a similar fashion to other EW version of the first five Gundams and included in New Mobile Report Gundam Wing: Frozen Teardrop as well as Mobile Suit Gundam Wing Endless Waltz: Glory of the Losers. It is later given additional equipment known as 'Sturm Und Drang' that can be used for both defense and offense.