Ophion

Artifice Ophion or Ophion is an Artifice in Xenoblade Chronicles 2 and Torna ~ The Golden Country and a in the former. Unlike other Artifices, Ophion can be only be controlled with the Omega Fetter during the events of Xenoblade Chronicles 2.

Appearance
Unlike other Artifices, Ophion has a serpentine appearance, and its head is organic with six protrusions that are placed in a hexagonal manner around the center. On top of its head is another humanoid body with a single glowing red eye, which (unlike other humanoid Artifices) lacks the Aegis core–shaped crystal on its chest and instead features a spherical core.

Story
At the conclusion of the Aegis War, during the party's final confrontation with Malos at the Soaring Rostrum, Mythra summons Ophion to fend off Malos's Gargoyles. Malos, however, anticipated this and hid several Gargoyles in the Cloud Sea, which overwhelm Ophion and destroy it, causing it to sink into the Cloud Sea.

At an unspecified point in the following 5 centuries, Ophion was revived and was tasked with guarding the World Tree from travelers. To this end it carved the Great Void around the World Tree.

When Rex's party attempts to reach the World Tree by borrowing Umon's boat, Ophion attacks them without warning. Pyra recognises Ophion, but does not understand why she cannot control it. Rex manages to gain enough distance to avoid its attack, causing Ophion to retreat back into Cloud Sea. The party is then swallowed by the Urayan Titan.

After manages to take both the Omega Fetter and Pyra in Tantal, and after Malos restores his powers, he calls forth Ophion using the Omega Fetter at the Gotrock Oracle Ruins. Ophion's autonomous attack instinct activates and it attacks Malos, who blocks the attack and promptly reprograms Ophion to follow his will.

After Rex and Pneuma defeat Jin, Malos summons Ophion to destroy the party, only for Siren to intervene. Enraged, Malos orders Ophion to attack Siren in retaliation. Eventually, Ophion manages to pin Siren into a cliff and fires a destructive beam. The resulting explosion destroys a portion of Gotrock Oracle Ruins, sending Jin and the party plummeting into the Land of Morytha. With Ophion gone, the Great Void gradually disappears over the course of days.

As an enemy

 * Artifice Ophion (Gotrock Oracle Ruins)