Kiara Sessyoin

Kiara Sessyoin is the Master of Caster in Fate/Extra CCC and the game's true antagonist.

Background
She is also a master who participated in the Moon Cell Holy Grail War.

Appearance
Her attire resembles that of a Japanese Buddhist nun; she wears a tight dress with a slit up the left side exposing her leg. After consuming both Passionlip and Meltlilith, her appearance changes to a demon.

Prologue
When Kiara was first introduced, she assumes the role of Taiga Fujimura; the homeroom teacher of Hakuno Kishinami and Shinji Matou.

Chapter 1 - Backyard of Eden
After Hakuno shifted to the Far Side of the Moon Cell, Hakuno was tasked to recruit other Masters to join the Student Council and encounters Kiara, who claims to have lost her memories. Kiara tells Hakuno that she has no interest in joining the Student Council, and reveals her servant Caster and refers him by Andersen. Andersen then warns Hakuno not to trust Kiara.

When Hakuno collected all the SG information from Rin Tohsaka, Kiara helps Hakuno to enter Secret Garden to find and face the real Rin.

Chapter 5 - Iron Maiden Princess
Later in the fifth chapter, Kiara starts showing puzzling behaviour such as making herself busy whenever Hakuno tries to make contact with her.

She is seemingly killed by Meltlilith when she sneaked up behind Kiara.

Abilities
Kiara absorbs both Passionlip and Meltlilith, and through Caster's Noble Phantasm and the Moon Cell, she reaches a similar existence to a True Demon. She becomes known as Heaven's Hole (, ?) and gains the Noble Phantasm, Angra Mainyu/CCC.