I'm trying to do the quest "Memory of Sai Mota" "Search for scraps of Sai Mota's necklace on the moon by defeating nightmares with arc abilities. Stronger combatants grant more progress" TBH it's not helped by the fact that I'm not clear on what constitutes an arc ability and what does not, or if there are any other requirements for the quest. I can see the character has a pick of abilities, Sunbreaker, Sentinel or Striker... not sure if any of these are "arc" or if only some or all of the actions for each ability count as arc - as per usual there's little to no explanation in-game. My character is a Titan subclass and I have equipped Sunbreaker abilities. I entered the lost sector in Sorrows Harbour on the moon and killed nightmares using Hammer of Sol from my Sunbreaker abilities (bound to `F` on Stadia). No necklace fragments dropped. What am I doing wrong? Do I need to use a specific ability? Or specific actions from a specific ability? Or what else do I need to do? Or is there some other pre-requirement that I need first?