Dagannoth Rex: how to defeat it (Ironman guide)

Tier

Early

Combat level

303

Style

Magic

Requirements

Waterbirth Island (Fremennik Trials recommended). Magic with Trident/Iban

Why kill it as an Ironman

Berserker ring (best melee ring), Warrior ring, Dragon axe. Rex is safe from a safe spot.

Loot

The live drop table (wiki rates) and the drop simulator are in the app. ⚔ Open in the interactive guide

Rex is the melee king and the easiest of the 3: get in unnoticed, reach the east wall and hit him with magic until he gets stuck on the wall. The Spinolyps in the water are what drains your supplies.

Left icon: what hits you. Right icon: what to pray.

→

Dropping in (Prime)

On the way down Prime hits with magic for up to 50. Protect from Magic BEFORE the ladder and run along the south to the east wall.

→

Stuck Rex

Attack him with magic from the east wall. As he approaches, Protect from Melee and move north or south until he is stuck and can't reach you.

→🚫

Spinolyps

From the water they poison you (starts at 6) and drain 1 Prayer per hit. Melee armour (high ranged defence) and antipoison or a Serpentine helm.

1. Waterbirth Island, descend to floor 6. Bring a Rune thrownaxe and Pet rock (or the 85 Agility shortcut, 80 with a Summer pie).
2. Protect from Magic before the ladder into the lair.
3. Enter and exit via the ladder until you can run along the south side without Prime or Supreme noticing. Reach the east wall.
4. Rex with long-range magic; Protect from Melee and move north/south until he's stuck. Kill him from there.
5. Loot and wait for the respawn. Guthan's, blood spells or SGS on the Spinolyps heal you while waiting.

Iban's staffTrident of the SeasHelm of NeitiznotGranite bodyRune platelegsBarrows glovesOccult necklace

Typical inventory

3

3

14

Rune thrownaxe · Pet rock · Prayer potion(4) x3 · Superantipoison(4) x3 · Pineapple pizza x14 · Teleport to house (tablet) · Rune pouch

• 💡 Rex has almost no magic defence and since 2025 is 35% weak to earth: Earth Wave with a Staff of earth (or Twinflame staff) is a cheap alternative to a Trident. Wear full melee armour for the ranged defence and you'll still hit him.
• 💡 You can log out in the safespot and return to the same tile. Elite Fremennik Diary: noted bones. POH portal to Waterbirth.
• 💡 Multi-bite food (Pineapple pizza, 65 Cooking) is worth more per slot: little damage taken and lots of downtime.

Tap a video to play it. Source: OSRS Wiki (CC BY-NC-SA 3.0).