Skill Up & Ascension MaterialOminous bones wielding curses.
Fuyuki: Unknown Coordinate X-C is the best AP-saving location to farm Evil Bone. You'll get around 2x Evil Bone by spending 40 AP.
Fuyuki: Unknown Coordinate X-C is the best time-saving location to farm Evil Bone. You'll get around 6x Evil Bone by spending 150 AP.
Here is a list of servants that need Evil Bone to perform Ascension and Skill Up.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
5 Star Servants Tier List: Best Servants [5/9 updated!]
Best Servants [★4]: 4 Star Tier List
Halloween Strike! Event Missions [JP Halloween 2017]
Best Craft Essence: Craft Essence Tier List
Cu Chulainn (Alter, Berserker)
Jeanne d’Arc (Alter)
Cheer for Master
Demon King of the Sixth Heaven
Talk on the Heated Sands