The guildie that told me about this quest chain tells me that only a handful of players know about this. I wanna make sure everyone knows about this.
The level 63/64 quest chain is started by talking to Crull Grafu in the Lakeside Graveyard. This initiates Young Lord Grafu which directs you to go to Kampel Town and talk to the mayor, Sean Card. After another quest from him (Tragic Past) he starts the final (repeatable) quest, Lost Soul (Endless Night).
This final quest leads you and 4-6 others to escort Crull Grafu into the Graveyard where he becomes the Abyssal Knight. Cleanse him of his sins so Crull Grafu may rest in peace.
The repeatable quest, Endless Night, may only be done once per day, but it has a very large XP reward (726,733), and 15 Phirius Token Coins rather than the usual 10.
First Quest: Young Lord Grafu