Tenebrion's Keep

Solution

Obtain Tiny Crystal Shards from the following locations in and around Tenebrion's Keep: Poppy Field, Curator (outside TK), Tower, Basement (accessed via EP Tower). The shards are then combined to form a Crystal which directs the user though Tenebrion's Zodiac Maze, which is accessed via a stairwell south of Tenebrion's Conference room.

Completing this quest yields the Ethereal Sword, which increases the user's Atkus by a percentage.