Sheath of the Secret Source

Materials

Trophies

3★

Character and Weapon Enhancement Material

Comes from a now-defunct Secret Source Automaton.

It appears to be the mechanism by which the Secret Source Automaton was powered, but its core is now empty.

Guide:

Secret Source Automaton route (Axis of the Secret Source, Sheath of the Secret Source and Heart of the Secret Source)

Sources:

Dropped by Lv. 40+ Secret Source Automaton: Hunter-Seeker

Stardust Exchange

Used by weapon ascensions:

Peak Patrol Song

Ash-Graven Drinking Horn

Footprint of the Rainbow