Refrain is a limited CE only available in Kara no Kyoukai (The Garden of Sinners) event.
For the duration of "Kara no Kyoukai (The Garden of Sinners) event", this craft essence gains additional effects.
Work in progress...
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
4th Singularity: London
5 Star Servants Tier List: Best Servants [5/9 updated!]
Vlad III
Best Craft Essence: Craft Essence Tier List
Caster
Forbidden Page
Dragon's Meridian
Ereshkigal
Arthur Pendragon(Prototype)
Gorgon
Black Holy Grail (The Black Grail)