Skill Up & Ascension MaterialThe fang of a dragon. Dragon Tooth Warriors are created using these fangs.
America: Deming (Free Quest) is the best AP-saving location to farm Dragon Fang. You'll get around 6x Dragon Fang by spending 170 AP.
Babylonia: Eridu (Free Quest) is the best time-saving location to farm Dragon Fang. You'll get around 6x Dragon Fang by spending 210 AP.
Fuyuki: Mobile Coordinate No.0 (Free Quest) is the fastest location you unlock to farm Dragon Fang.
Here is a list of servants that need Dragon Fang to perform Ascension and Skill Up.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
Enkidu
Kid Gil
Karna
Ruler
Eric Bloodaxe
Ereshkigal
Arthur Pendragon(Prototype)
Gorgon
Black Holy Grail (The Black Grail)