OSRS Chambers of Xeric (CoX) Guide: Raids 1 Explained

Prepare to delve into Old School RuneScape's first-ever raid: the Chambers of Xeric (CoX)! Located beneath Mount Quidamortem, this sprawling, procedurally generated dungeon pits teams (or skilled solo players) against a series of challenging combat encounters and skilling puzzles, culminating in a multi-phase battle against the formidable Great Olm.

This guide provides an overview of the Chambers of Xeric, including accessing the raid, understanding the layout and points system, common rooms, resource gathering, and key strategies for the Great Olm fight.

Accessing the Chambers

  • Location: Mount Quidamortem, Kebos Lowlands.
  • Travel:
    • Lovakengj Minecart Network (fastest initial).
    • Speak to Mountain Guide near Shayzien's Wall/Fairy Ring BLS (unlocks shortcut via Book of the Dead).
    • Xeric's Talisman teleport (Xeric's Honour - requires Ancient Tablet drop from CoX).
  • Requirements: None mandatory, but high combat stats (85+) and decent skilling levels (Herblore, Farming, Mining, Woodcutting, Hunter, Fishing, Thieving - 55+ recommended) are crucial for success and contribution.

Raid Mechanics & Layout

  • Team Size: 1-100 players (scaling difficulty). Commonly done in teams of 2-5, but solos are possible.
  • Layout: Randomized dungeon layout across 2-3 floors before the final boss. Layout choice (Normal, Large, Full) affects room count and pathing. Challenge Mode has a fixed, longer layout.
  • Rooms: Each floor contains a mix of:
    • Combat Rooms: Fight specific bosses/monsters (e.g., Tekton, Vespula, Vanguards, Guardians, Shamans, Mystics, Muttadiles).
    • Puzzle Rooms: Require skilling/mechanics (e.g., Crabs, Ice Demon, Thieving, Tightrope).
    • Scavenger Rooms: Kill Scavenger beasts for resources (Herblore secondaries, tools, planks). May contain skilling shortcuts for points.
    • Resource Rooms: Contain nodes for Farming, Fishing/Hunter, Woodcutting, Mining (usually one per floor).
  • Points System: Crucial for rewards.
    • Earning Points: Dealing damage, completing puzzles, using resources (food/potions made inside), building storage units, clearing shortcuts.
    • Losing Points: Dying significantly reduces your personal points (-40%) and can penalize the team's total points if you have very few.
    • Impact: Higher total team points = better chance at unique loot. Higher personal points = more quantity/value in standard loot rolls. (Unique chance caps around ~570k total points).
  • No Items In/Out: You cannot bring external supplies. Everything needed (food, potions, some gear upgrades) is crafted inside using gathered resources.
  • Safe Death (Mostly): Standard deaths are safe (items kept), but raid-specific items (potions, food, planks) are dropped on death. Hardcore Ironmen still lose status.

Resources & Preparation Inside

Success often depends on efficiently gathering and utilizing resources found within the Chambers:

  • Food: Catch Fish (Fishing Spots) or Bats (Hunter nodes). Cook on fires (dropped by monsters/Ice Demon room). Higher tiers require higher skills.
  • Herbs/Potions: Farm seeds (Golpar, Buchu, Noxifer) dropped by monsters/found by raking. Gather secondaries (Stinkhorn, Cicely, Endarkened Juice) from Scavengers. Make potions in Gourd Vials (fill at water sources). Higher Herblore unlocks better potions (up to Overload+ at 90).
  • Storage Units: Built using Mallignum Root Planks (from Scavengers) and Construction skill. Allow shared storage for resources and private storage for gear swaps/drops. Crucial for team coordination.

Common Rooms Overview (Brief)

  • Tekton: Melee boss weak to Crush. Avoid his attacks by running or flinching. Hits hard. Drops Overloads.
  • Vespula: Flying boss weak to Ranged/Magic. Heal Lux Grubs to prevent Vespine Soldiers spawning. Destroy Abyssal Portal while Vespula is grounded. Drops Prayer Enhances.
  • Vasa Nistirio: Teleports players, fires boulders. Heal Glowing Crystal quickly (Stab weapons best) before Vasa heals from it. Drops Revitalisations.
  • Vanguards: Trio (Melee/Range/Mage). Weak to opposite style. Keep HP balanced or they reset/heal fully. Shuffle positions periodically. Drop Combat potions.
  • Guardians: Two statues weak only to Pickaxes (Crush style). Dodge falling rocks. Drop seeds.
  • Lizardman Shamans: Similar to outside. Dodge poison spit and purple spawns. Drop seeds.
  • Skeletal Mystics: Magic users. Protect from Magic recommended. Weak to Ranged/Crush. Drop seeds.
  • Muttadiles: Small one (Melee/Range), then Large one (All styles + Shockwave). Prevent healing from Meat Tree (chop it down or bind Muttadile). Drop Overloads/Revits/Xeric's Aids.
  • Crabs Puzzle: Reflect orbs off colour-matching Jewelled Crabs onto crystals. Protect from Melee.
  • Ice Demon Puzzle: Chop Kindling, light braziers to thaw Demon. Fight Demon (weak to Fire spells, use Protect Missiles/Magic). Drops secondaries.
  • Thieving Puzzle: Loot chests for Cavern Grubs, deposit in trough to feed Corrupted Scavenger. Avoid poison traps. Drops secondaries.
  • Tightrope Puzzle: Kill Deathly Mages/Rangers, cross tightrope (Agility req), grab Keystone, use on barrier. Can be skipped by skilled players.

The Great Olm (Final Boss)

A massive, multi-phase encounter fought across three lanes. Requires team coordination and understanding complex mechanics.

  • Structure: Fight Left Hand (Melee), Right Hand (Mage), and Head simultaneously. Hands must be disabled to damage Head (except final phase).
  • Weaknesses: Left Hand = Melee, Right Hand = Magic, Head = Ranged.
  • Attacks: Uses Ranged (crystal burst) and Magic (dragonfire) projectiles. Also uses Spheres (Red=Melee, Green=Range, Purple=Mage - pray correctly to block high damage/prayer drain). Has phase-specific powers (Acid, Flame, Crystal).
  • Specials: Crystal Burst (falling crystals), Lightning (wall hazards), Swap (teleport).
  • Phases: Typically 3 standard phases + Head phase. Olm switches sides/powers each phase. Penultimate phase involves disabling both hands simultaneously while Left Hand heals. Final phase involves killing the Head directly while dodging falling crystals.
  • Strategy: Requires roles (Melee hand, Mage hand), managing specials, dodging hazards (crystals, lightning, fire walls, acid), coordinating attacks, potentially using "running" or specific tile methods to manipulate Olm's head turning/attacks (advanced). Defence reduction specs (DWH, BGS) are crucial.

Conclusion

The Chambers of Xeric is a cornerstone of OSRS endgame PvM. Its blend of combat, skilling, and puzzle-solving within a randomized environment offers high replayability and requires teamwork and individual skill. Mastering the preparation phase, efficiently clearing rooms, and coordinating against the Great Olm are key to success and earning some of the most iconic and powerful rewards in the game.

Struggling to find consistent teams or master Olm's mechanics? Our veteran players can guide or assist you through raids via our OSRS Raids Services. Ensure your account has the necessary stats with OSRS Skilling Services and gear funded by OSRS Gold!