Chewed Aethril Stem

Chewed Aethril Stems drop from the following nightborne, nightfallen, and withered in Azsuna:
 * Nightfallen Hungerer
 * Nightfallen Overseer
 * Withered Scavenger
 * Withered Mana-Rager
 * Withered Exile
 * Ishkaneth
 * Withered Fanatic
 * Tyndrissen

As a quest objective

 * Desperation Breeds Ingenuity