Dagannoth Rex

Dagannoth Rex is the melee based Dagannoth King found in the depths of the Waterbirth Island Dungeon, along with fellow Dagannoth Kings Dagannoth Supreme and Dagannoth Prime. Rex is the only monster to drop the coveted Berserker ring and Warrior ring, which can be sold for hefty prices. He, along with the other Dagannoth Kings, can also drop the rare Dragon axe.

Strategy
Dagannoth Rex has an extremely low magic defence. Therefore it is recommended to use magic against him for better hits; popular choices are Slayer dart, Fire Wave and God Spells. For best damage per second, players should use a Staff of the dead for the 15% damage boost (stacks with Charge spell), as well as it has the ability to autocast Flames of Zamorak. Another more popular alternative is the use of the Trident of the seas. Using any of these strategies in conjunction with the slayer helm (i), a player can now deal out extra damage if they are on a dagannoth task. Occult necklace may be used with Staff of the dead or Tridents of the seas for an extra 10% magic damage.

Due to his large size, the fact he uses melee attacks only and the surroundings he is in, it is recommended to get him stuck on one of the ridges of the lair and safespot him (note that Spinolyps will still be constantly attacking while you're safespotting him). Many players use high-level armour such as Barrows armour which give high defence bonuses while still being able to hit Rex constantly with spells due to his very low magic defence, even if their magic attack bonus is below zero. Players who use Guthan the Infested's equipment are advised heal themselves on the Spinolyps while waiting for Rex to re-spawn to help preserve food and potions.

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Weapons

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Armour

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Potions

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Gems, Ores, and Bars

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Food

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Talisman Table
** The chance of hitting the talisman is 1/128 with a 1/7 chance of any specific talisman

Source: https://twitter.com/JagexAsh/status/745561134040645633

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Other

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