The quest consists in finding all the obelisks scattered around the worlds. This quest activates after you have found the first one.
Treasure coordinates: 129,53. - You cannot find the treasure before you have found all 7 obelisks.
Excerpt from all obelisks:
Your journey starts at the gate of the Seaharbor (Seahaven is what is meant here). Now, take ten steps towards the Sea of Storms. Turn left and take twenty (there is an error in the game, there should be twelve). Turn right and take eleven steps. Turn left and take nineteen steps (requires blessing from the Water God). Turn right and take three steps more. Turn right again and take the final step. Under the rock on the left, there is a buried treasure (a relic).