Easy boss, bring 5-6 decent Rex's surround the boss when it land preventing it from flying high. Once it try's to fly it will be stuck and you can kill it easy, have one or two people on Rex's walk around and kill death worms and remember where the bags drop. Once the rock elements come out the two not attacking the boss go back and kill the boss once you defeat the boss go to the death worm bags collect the black pearls. EASIEST BOSS.

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