The Phönix is a High-Mobility-Type Legion excelling in stealth and close-quarters combat. It is capable of greatly outperforming its contemporaries and the XM2 Reginleif in melee. Its ability to camouflage itself using a swarm of Eintagsfliege renders it undetectable, while its agility and mobility allows it to swiftly strike with its two high-frequency chain blades. The Phönix's weakness lies in its light armor, having sacrificed protection for speed. A Phönix was able to be dispatched by Shinei Nouzen using a rifle firing a barrage of 7.62 mm armor-piercing rounds, an nigh impossible feat to be performed on other Legion units.
The Phönix was first discovered by the Eighty-Sixth Strike Package during the Charité Underground Labyrinth Operation, where it had annihilated the Phalanx squadron, a group of skilled Processors. Presumably, it is one of the Legion units not originally developed by the Giadian Empire.