Summer's Rain can be obtained by having Asagami Fujino reach Bond Level 10.
Summer's Rain is Asagami Fujino' Max Bond CE and exclusive to her.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
5 Star Servants Tier List: Best Servants [5/9 updated!]
Best Craft Essence: Craft Essence Tier List
Nero Claudius
Scathach
1st Singularity: Orleans
Quetzalcoatl
Medal of Great Knight
Ereshkigal
Arthur Pendragon(Prototype)
Gorgon
Black Holy Grail (The Black Grail)