This could be open for story addition and more quests. I was thinking about adding fey slaying to a weapon type of my choice. Then thought that, I sure wish there was some 3 layed chain quest I could do to get this. The Focusing Gems seemed the perfect way to tweak a working system and loved the way they worked. If they were tweaked slightly again to check for max weight of mods then a slayer gem could be created. Maybe even many quests able to be made to go after just the type of slayer you need. Maybe even gem/slayer could be a 4th lv of the quest where you use it to finish the quest type you are on.