Anga's Ruby

[Zhuangzi]

Yep, you missed it. In Freedom Isles there is a ship (I forget the name) that turns into a ghost ship every night. You can talk to the captain, and he gives you the quest to get an 'Indulgence' from the Temple in Marshan Swamp. Give him the Indulgence and you get Anga's Ruby.

So you will need to go back to Freedom Isles, then Darion, then Freedom Isles again. A pain, but WELL worth it if you want to use Sprites/Lake Fairies especially, which IMO are the best attack units in the game.