The Sayaniona's can be seen in the forest north of RuneScape Gold Solar Isle. Go back to the hut of the cheif. Head back to the hut and climb the rockslide. The boulder is broken by using the grapple. Next, attach the rope to the boulder, and pull it. The boulder will drop and roll toward you. Then, reattach the hook to the rope, and begin to swing around the boulder. (Require 55 Agility)

You will be led into the Sayanionas' lair. They can attack you if they are furious. Run past the chamber filled with baby Sayanionas (level 25s). They're useless currently. You must pass by the Lesser Sayanionas, until you reach a room with Greater Sayanionas. 

These are level 90, and they are hard to defeat. Keep your Guard against Melee active and continue filling up with prayer pots. The horn should be removed after it has passed away. Use a mortar and pestle to grind it. It's the Sayaniona's Horn. The next step is to extract the water.

Go back to the village at Solar Isle, and go into the Cheiftain's hut. The ladders go up, while the other one descends. Grab the pile of rubble and then climb the ladder. Press the rubble to rub it, and you will recover an Enchantment Rock. Pick up a pickaxe to collect magical dust from the box in the west end of the corner. Take the ladder up, and up the other ladder. Fill the vial with Water of the Ancients. Then add the magic dust, and you'll have a vial of Magic Water.

Now, you need to mix the herbs in the order in the scroll. 3 Sunbleached Herbs, 1 Sunset Herb, Ground Sayaniona's Horn. You will receive a vial of Buy OSRS Fire Cape Enchanted Posion. Use it with the Sunrisen Staff. A Solarus Staff will be given to you. It is the only weapon that is able to eliminate Ethernals. Return to the Cheiftan.