Getting Started

First off, visit the Gypsy in the city of Varrock.

She can be found in the tent next to the Clothing Shop (red circle on the map), and when you talk to her she wants to read your future, but you need to "cross [her] palm with silver". In other words, just give her 1 gp. You can then choose any of the three options. Then ask her who Delrith is, and she talks of an old tale…

Dark wizards gathered in beneath Varrock to summon the Delrith, a vicious monster that they hoped would render Varrock into rubble. Luckily, Wally, the hero, came just in time.

And our (humble) hero managed to defeat the Demon and bind him within the stone Circle that we see now below Varrock.

Ask how you can kill the demon, and she says that you need a Silverlight Sword and an incantation -- be sure to write down the incantation that she gives you (it's different for everyone)! She tells you to talk to Sir Prysin about the sword.