Familiar Creation

Typically the skill of a Caster-class Servant.
Titan Altera also possesses this skill, at EX rank.
The purpose of this skill is to create a familiar that acts as an extension of its creator that can be controlled from afar. In Altera’s case, it is more like creating an alter ego or an avatar.
In need of a physical body to destroy civilization on earth, since her real body is made of information, Altera uploaded her data from the Moon and used the spiritrons on Earth to create a physical form.
This is how the fearsome White Titan appeared on Earth 14,000 thousand years ago. Altera also created an avatar in the form of a Servant, allowing her to move around freely inside of SE.RA.PH.

Fate/EXTELLA material: Encyclopedia of Fate EXTELLA