Galactica Saber is the "ultimate Saber" who ruled the oceans of a radiant planet from the distant skies. She is said to be the "Saber of Sabers" that every Saber-user dreams of. She boasts of her ability to fight space monsters unassisted.
Galactica Saber is a super-rare Capsule Servant specially drawn by Takeuchi Takashi. Leysritt tells Shirou that by collecting all the Saber editions from limited-time Servant draws, there's apparently a rare chance of drawing Galactica Saber Final Edition. Gilgamesh has this servant in his possession in Shirou's ending in Celebloomers ending. Gilgamesh spent the entirety of his treasury on collecting many super-rare Servants. He hugs it every night while he goes to sleep.