I just wanted to say I absolutely loved the DRK 30-50 quest.
You go into Ishgard and find rumors about a fallen knight, so you go check the Brume. You find a fallen knight clutching a DRK soul crystal, then hear a voice and pass out. The knight's up and ready, identifying themselves as Fray, and offers to train you in the ways of the Dark Knight to go rescue a falsely-accused woman.
Throughout the quests Fray accompanies you, begrudgingly helping you to rescue people and fight others' battles while chewing out the people who are ungrateful for what you did for them (lookin' at you, Limsan merchant guy!). They even comment on some things that seem strange, such as Leviathan. Perhaps Fray was a member of the Company of Heroes?
Finally comes the 50 quest. You help some Ishgardian soldiers kill some monsters, but are then accused of heresy and told to report to Whitebrim, where you may have to surrender your weapon. You get there, and Fray has already beaten down the standing forces and says they'll never surrender their weapon after what happened in Ul'dah. Then Fray tells you the truth - the "Fray" you know is you, or rather, your psychological shadow who manifested using the Dark Knight soul crystal as a medium. This "you," your shadow or dark side, is sick of everyone lumping their problems on you and offering nothing but thanks (or less) in return and has no problem with cutting down anyone who gets in the way of your justice. "Fray" explains you knew Fray was dead all along, but you wanted a mentor to teach and guide you in the ways of the Dark Knight, so the Soul Crystal resonated and brought your shadow out to possess Fray's dead body for the purpose of instructing you.
Your shadow then leaves Fray's body and manifests as you decked out in the DRK Artifact Armor and wielding the DRK Relic Weapon, and you're forced to fight against it for control of your soul. You defeat it, and with the help of the populace of Whitebrim, accept it as a part of you. Your shadow remorsefully agrees with your decision to continue playing the hero despite your darkness having been glimpsed, reminding you they'll always be there when you need them.
Very psychological and introspective, very well done. I haven't seen anything so psychologically complex outside of an Persona game or Spec Ops: The Line. I'm still working on Heavensward, so I don't know how the 50-60 questline plays out, but I have high hopes for it!