Yaldabaoth

Yaldabaoth (, Face Jaldabaoth), also known as Gold Face, is an antagonist of Xenoblade Chronicles.

Appearance and personality
Yaldabaoth is a Face Mechon covered in gold armour. It is designed differently than the other Faces in that it is not held together by spindly connectors, but thickset limbs that give it much more of a humanoid form. It features spiralling structures around its shoulders and wrists, a U-shaped structure on its back, a long coiling tail, and fittingly, an m-shaped flourish on its head that resembles that of its pilot Egil.

Unlike the other Faces, there is little implication that Yaldabaoth is its own "person". Once it appears onscreen clearly for the first time, it is understood to be merely a shell of its pilot.

Story arc
Yaldabaoth is first glimpsed in a few teaser cutscenes, musing to itself about how the Mechon's effort against Bionis are going. Its first clear appearance is at Valak Mountain, when it arrives to break up the fight between Shulk's party and the misbehaving Metal Face. The pilot of Yaldabaoth, Egil, states that it is the strongest Mechon ever built while ignoring Shulk's questions. He then takes Metal Face and Face Nemesis back to Mechonis.

Yaldabaoth is next seen in the depths of Galahad Fortress. Egil is forcing Face Nemesis to unwillingly attack the party, and gives them the choice of being killed by her or by him. Face Nemesis rebels, and in the aftermath the fortress collapses. Yaldabaoth watches the explosions from a distance as Egil thinks about what could have happened.

Once the party meets Egil again, he fights them on foot. But once pushed back, he summons Yaldabaoth to crush them with, and prevails with ease. But he is barred from finishing them by the efforts of Meyneth, revealing herself to Egil to try and shock him out of his blind revenge. Instead, Egil decides that the last person he cared about has left him, and chooses to ignore the party and move on to the core of Mechonis. There, he inserts Yaldabaoth into a control mechanism that allows him to take command of the Mechonis itself.

Egil meets the party once more as they attempt to stop him, fighting them from inside the core-connected Yaldabaoth. He is defeated, and Shulk cuts off Yaldabaoth's head to expose Egil inside. This does not limit Egil's ability to use Yaldabaoth to challenge the evil Zanza in the aftermath, and as the Bionis awakens, Yaldabaoth is cut in two. It is then destroyed with the rest of the Mechonis.

As a boss

 * Gold Face
 * Yaldabaoth (Agniratha)
 * Yaldabaoth (Mechonis Core)