OZ-13MS Gundam Epyon
A Gundam-type Mobile Suit developed by Treize Khushrenada based on the Tallgeese and 5 Operation Meteor Gundams. True to Treize's philosophy of combat, it was only armed with melee weapons: a heat rod and a very high-output, large beam saber that is capable of destroying space fortresses. It also possessed the ability to transform into a flight mode (with a twin-headed dragon design), and was equipped with the fearsome Epyon System, a modified version of the ZERO System that enabled its pilot to control the battlefield.
While it was originally Heero Yuy that relieved Treize of the Epyon, he later exchanges the unit for the Wing Gundam Zero with Zechs Merquise after a brief scuffle.