As my 100th task, Duradel kindly decided to let me have something new!
An elemental shield is VITAL here, as is protect from melee and d'hide. Bring 4 p pots, and the rest sharks, as they can deal a lot of damage. They occasionally drop mithril bolts, and quite often drop 2x crimson charms.
Also, they have the possibility of dropping the Draconic Visage.
They are at the end of the Port Sarim dungeon.