Resonators Monsters Weapons Items
LF Polygon Core Development Materials A material used for Weapon & Resonator Ascension and Skill Upgrade.

A fractured polygonal Tacet Core with an intricate, terraced pattern. Cracks can be found on its frail spiral structure. Seems to be a simple power unit of a Tacet Discord.
Sources
Synthesis - Conversion
Masked Reverie
Store
Drop: Clamorlings or Tranquilites
Forgery Challenge - Ragunna