OSRS Delve Boss Guide: The Doom of Mokhaiotl

Deep beneath the Tlati Rainforest lies a new type of challenge for Old School RuneScape's adventurers: the Doom of Mokhaiotl. This giant, demonic insect is the game's first "delve" boss, an encounter that gets progressively harder the deeper you go, pushing you to risk your rewards for a chance at even greater treasures.

This guide will cover the core mechanics of the Doom, its attack styles, and what you need to know to survive your first delve.

What is a Delve Boss?

The delve mechanic is a "push-your-luck" system.

  1. You defeat the boss at Delve Level 1.
  2. It burrows underground, leaving behind loot.
  3. You can choose to claim your loot and leave, or risk it by descending to Delve Level 2.
  4. At Delve Level 2, the boss is stronger and has new mechanics, but offers a better chance at unique drops.
  5. This continues up to Delve Level 8 and beyond.
  6. The Catch: If you die at any point during a delve, you lose all accumulated loot from that run.

Core Mechanics & Attack Styles

The Doom is a primarily Ranged-focused encounter, though it uses all three combat styles. It is a demon, making demonbane weapons effective.

  • Standard Attacks: The Doom fires projectiles that you must pray against. Blue is Magic, green is Ranged, and orange is Melee.
  • Rock Throw: The boss launches a rock that explodes, disabling your protection prayers. You must quickly reactivate your prayer to block a follow-up projectile. As you delve deeper, this attack will fire more projectiles.
  • Demonic Larvae: Larvae will spawn and move toward the boss. If they reach it, they will heal the Doom and increase its power. These must be killed quickly.
  • Shockwave: The Doom will charge a massive shockwave attack. To survive, you must quickly attack two "volatile earth" nodes in the arena to create a moving earthen shield, which you must stand inside.
  • Acid Blood: Starting at Delve Level 3, the boss will spray acid on the floor, limiting your movement area. This acid persists between delve levels, making deeper runs much harder.

The Fight's Progression

As you delve deeper, new mechanics are introduced, creating a punishing but rewarding difficulty curve.

  • Delve 1-2: The introductory phase, focusing on basic prayer switches and the Rock Throw.
  • Delve 3-4: The boss adds the Acid Blood and Demonic Shield phases, requiring you to use demonbane weapons to break its shield.
  • Delve 5+: The boss gains the Burrowing ("Car") Phase, where it charges across the arena. You must hide behind fallen rocks to survive its devastating slams.
  • Delve 8+ ("Deep Delves"): The ultimate challenge, featuring all mechanics at their most intense, with fewer safe spots and a room filled with persistent acid.

Ranged is the preferred style for this fight.

  • Weapon: Twisted Bow is best-in-slot due to the boss's high Magic level. The Scorching Bow is a powerful demonbane alternative.
  • Armour: Masori (f) > Elite Void Knight Equipment.
  • Spec Weapon: Zaryte Crossbow or Dragon Knives are excellent for dealing high damage, especially during the 100% accuracy "car phase."
  • Demonbane Switches: You will need a demonbane weapon (like Arclight or a staff with demonbane spells) to deal with the shield phase and the larvae.

Conclusion

The Doom of Mokhaiotl introduces an exciting and challenging new PvM loop to OSRS. The delve system forces players to make tough decisions, balancing greed against the risk of losing everything. It's a true test of endurance, mechanical skill, and risk assessment that rewards the most prepared and persistent adventurers.

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