Once you have all four crystals, go to the rock pillar with crystals growing from it at ( -791, -447, 279 ) Copy/waypoint -791, -447, 279. Hovering your mouse cursor over some of the crystal growths will show a popup window saying "a drusy crystal", "an elestial crystal"... etc. Left click a crystal on the rock pillar and if you have a crystal of the corresponding type in your inventory, the crystal on the rock will begin glowing.
Once all four crystals are glowing, Earthlord Abnu'kal will spawn immediately.
He hits fairly hard. Soloable with a merc, but be careful.
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