Viyeldi

Viyeldi will explain how the three warriors need to be killed during the Legends Quest in order to obtain the Heart crystal needed to progress further in the quest. The spirit Echned Zekin asks you to kill him during the quest. He also has a combat level of 70. He pretends to be a hat on the ground until picked up. You can chose to abide by what he says, or you can kill him using the Dark dagger that Echned Zekin gives you at the source of the holy water spring. However, if you kill him, Echned Zekin reveals his true identity as the black demon Nezikchened, and will try to kill you again. However, now you will have to defeat the three warriors found in the cave again, in the third and final fight. You can skip this if you don't kill Viyeldi with the dagger and give it to Ungadulu instead, who will give you a Holy force card to use against and weaken Nezikchened for the two next fights. See the quest guide for more information.

Trivia
It was possible in 2005 to telegrab Viyeldi's hat. Dropping and picking it up caused the player to teleport back to the Viyeldi's cave, even if the player was in the wilderness or the duel arena. Jagex fixed this problem approximately 2 weeks after it was discovered, resulting in the first un-telegrabbable item.