Powerful Core

Obtained

 * Field: Lakeside, Mutant Forest, Pontus Ferrum, Porta Inferno
 * Dungeon: Weakened Lake in Dusk, Weakened Ruina Station, Weakened Tower of the Dead (B1F), Forgotten Temple (B1F), Forgotten Temple (B2F), Forbidden Island, Altar of Siena (B1F), Altar of Siena (B2F), Illusion Castle Underworld, Illusion Castle Radiant Hall
 * DX Dungeon: All

Used to craft

 * Basic Craft: Fury Potion (Lv 2), Force Core (High), Upgrade Core (High)