MF Howler Core Development Materials A material used to break through weapons, ascend Resonators, and upgrade skills.

The Tacet Core of a common Howler. After the Tacetite Bloom withers, a certain amount of Frequency Energy remains. Similar to the natural cycle of life, this frequency can probably serve as the sustenance for newcomers.
Sources
Synthesis
Drop: Howlers
Forgery Challenge
Weapon Shop