Model ZX

Model ZX (モデルZX) - The Ultimate Mega Man

History
Model ZX was created through Double Megamerge during the first ZX game, when Girouette gives Model Z to Vent/Aile shortly before his "death" at Serpent's hand. While Model ZX is treated as its own Biometal by name, Models X and Z are still separate Biometals and must always be Double Megamerged to create Model ZX. Unlike the other Biometals, this fusion grows artificial hair similar to Zero.

Power and Abilities
Model ZX's weapons are the ZX-Buster and the ZX-Saber, a combination of X's and Zero's signature weapons. Unlike Zero's weapons during the Mega Man Zero series, the ZX-Buster and ZX Saber are one in the same instead of the Z-Saber providing as a slot-in component of the Buster Shot Gun, as it is capable of transforming into one to the other freely, as shown in Aile's Double Megamerge sequence in ZX Advent.

Model ZX makes another appearance in Mega Man ZX Advent, as the only Biometal still in the hands of Vent and Aile, the rest having been stolen by Prometheus and Pandora prior to the events of Advent. The model fusion still possesses the same abilities as before, but with the addition of a new technique for both of them; Vent receives a combination of the EX-Skills, Tenshozan and Zanaiden, firing off a wave of energy while performing a rising slash and Aile receives the Tsuibangeki to allow her to plant the ZX-Saber into the ground with an downward aerial strike, spewing forth rocks from the earth upon contact.

Trivia

 * Model ZX will also appear in the upcoming iOS social RPG Rockman ×over, fused with Vent/Aile, and as the protagonist representing the Mega Man ZX series. It is currently unknown what role it will play in the game's story.