Where do I find the four chests needed to open the Final Chest?

The first time you enter that outer-space central hub thingy, there's a chest labeled the "Final Chest." When you try to open it, it tells you you need to "find its four hidden sister chests scattered throughout the four realms" in order to open it.

Where are these four chests located? And is it worth it?

No screenshots since I complete the game and uninstalled, but from memory:

1. To the right of the Legion quartermaster building (between it and the wall)
2. In the initial cave area of Hieberheim (don't recall exactly where it was)
3. At the end of a puzzle in a cave south of Sacred Stone
4. In the bushes behind the Wizard's House in Hunter's Glen

Theres a +Ability and a +Stat book inside (same as the ones from the Teller of Secrets) as well as a bunch of orange loot (not sure if leveled, I opened it at L20 and got L20 gear).

Remember to keep the Dusty Parchments, they give you the combination to open the last chest. Also ALL 4 have to be in one characters inventory when you talk to the chest.