Yeh it is
http://runescape.salmoneus.net/quests/LegendsQuest.html
Now go south to the Shimmering Field, and look for the Recess next to it. Use your Crystal Heart on it, and you'll be able to pass. Run west, past the Lesser Demons, and you'll see some Boulders. Try pushing one, but a ghost named Echned Zekin will appear and stop you. Tell him that you're looking for Holy Water, and he'll tell you to kill Viyeldi. He'll also give you a Dark Dagger. If you want your own, drop it, speak to him again and pick it back up
Now, the path splits: you have two choices, a shorter, evil, but more difficult one, and a longer, good, and easier one. If you choose the first option, you will have to fight the Fallen Heroes again in the last battle. Also, if you want to restock food and potions, the second path is the way to go.
Option One:
Go back to the Blue hat. Try taking it, and then use the dagger on Viyeldi. This will make the dagger glow. Take the dagger back to Echned Zekin, who will show you his true form: he is the black demon Nezikchened!