Saber (Fate/Extella)

Saber (セイバー) is a Saber-class Servant appearing in Fate/Extella.

Identity
Saber's True Name is Altera (アルテラ), or

Appearance
She has white hair and red eyes.

Fate/Extella
Saber is a playable character and her main party consist of herself, her adjutant Gilgamesh, Jeanne d'Arc, and Iskandar.

Attilaight Cell
Saber Mars (セイバー・マルス) is a form taken in Fate/Extella. Attilaight cell (巨神アルテラ) is the Anti Cell that fell to the Moon after being purged by the Velber. The "Titan" Anti Cell that absorbs mana from the civilization she destroys and uses it to grow bigger, designed to destroy itself once the task is done.

She invaded SERAPH as an Anti Cell, and also sent her own data to Earth to create a material body (avatar), invading both at the same time. She did huge damage to both, but was beaten by the Moon Cell on the Moon and by the wielder of the holy sword on Earth. On Earth she became a corpse, but on the Moon she was sealed since Moon Cell had no way to wipe her out. The Altera (Moon) stayed in the Star of Tears which became the separated "unknown territory". 14000 years past and Altera wakes up as the Velber approach the galaxy again.