After mission 5, make sure to have Grotius, so one can talk to him about being lonely. Then you will talk to Nightling (he's reading a book near the west side of the Queen's Palace) about Grotius. If everything is done right, then Grotius will give you an orb.
At the start of mission 6, one can go to Lake Alto and talk to Pirate Pete. As Pete suggests, one will need to kill the Spriggats around the boat before the side mission can begin. One will then return to the dock to speak to Pete again. One will quickly have to search the nearby islands and shores for four treasure chests on the islands. After completing the mission Pete will give the orb as a reward.