How do you finish Merlin's crystal in runescape?

Answer 1

There is an orange, circlish shape on the ground behind the camelot castle. Drop bat bones on it to unleash a demon that will not attack. But, before that, in the south-eastern corner of varrock there is an altar. examine or check or whatever it says on it and it will give you some words. So, now back to camelot. drop the bones, say the words, wield excalibur, go upstairs in the castle and break the crystal.