Keira Matz's questline is 100% worth your time. Her questline starts with "The Magic Lamp," after finishing the main quest, "Wandering in the Dark." Completing it will lead you to "Keira Matz's Invitation," where you can meet the witch, learn more about the magic lamp and agree to help her with the curse that lies over Fyke Island. Just keep in mind that you'll have to do all of this before "The Isle of Mists," or your quest will fail, and you won't be able to access this questline. But, overall, it's a pretty cool questline with extraordinary events and memorable gameplay moments - don't pass it up!