Ambiguous Chalice can be obtained by having Semiramis reach Bond Level 10.
Ambiguous Chalice is Semiramis' Max Bond CE and exclusive to her.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
Crystallized Lore
Caster Piece
Shining Gem of Spells
Iskandar
Mephistopheles
Gorgon
Mata Hari
Ereshkigal
Arthur Pendragon(Prototype)
Black Holy Grail (The Black Grail)