I completed the quest on a different character by accident than the one I picked up the awoken momento; if you did this all you need to do is dismantle the awoken momento in your primary slot on the character you picked up the momento and go pick up a new one from Petra Venj on the character you completed the quest with and then you can jump right back in to the shattered throne save spot and voila Wish Ender. Hope this helps.