Arachni’s Haunt is a dungeon in Guild Wars that is home to Arachni; a Ranger Spider boss found on level 2. There are also 3 other bosses found throughout level 1 and 2 of Arachni’s Haunt; Spider Matriarch, Lok The Mischievous, and Brood Warden. There are a multitude of monsters to be found in this dungeon that range from spiders, to plants, to ooze, insects, and elementals just to name a few. Most monster levels will be ranged from 20 through 24 with a few 28s and 10s thrown in here and there. 
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Don’t forget to grab the buff from your Beacon of Droknar or visit Dagnor Grubeater the collector who will gladly take 5 Lavastrider Appendages off your hands in exchange for an item of your choice or a handy dungeon map. In order to access this dungeon the quest Scrambled Reinforcements is needed to be active. To obtain this quest visit Commander Hixx. He is found in the south west corner of Magus Stones.