Thermonuclear Smoke Devil OSRS: The Ultimate Slayer Boss Guide

The Thermonuclear Smoke Devil, affectionately known as “Thermy” in Old School RuneScape (OSRS), is a formidable Slayer boss that offers both challenge and reward for high-level players. Requiring 93 Slayer to damage, this fiery fiend resides in the Smoke Devil Dungeon and is a must-know encounter for anyone pursuing Slayer mastery or hunting rare drops like the Smoke Battlestaff and Pet Smoke Devil. In this comprehensive guide, we’ll dive into everything you need to know about the Thermonuclear Smoke Devil in OSRS, from strategies and gear to its loot table and lore. Whether you’re a seasoned adventurer or a Slayer newbie aiming for the top, this blog post is your one-stop resource.

The Thermonuclear Smoke Devil is the boss variant of the regular Smoke Devil, a mutated cousin of the Dust Devil introduced to OSRS on January 26, 2005. Located south of Castle Wars in the Smoke Devil Dungeon, Thermy stands out with its unique mechanics and high Slayer requirement. Unlike its lesser kin, this boss can only be attacked during a Smoke Devil Slayer task (with one exception for the Western Provinces Diary), making it a specialized target for dedicated players.

Key Features of Thermy

Thermy isn’t just another monster—it’s a test of preparation and skill. Here’s what sets it apart:

• Slayer Level: Requires 93 Slayer to deal damage.
• Location: Found in a separate chamber of the Smoke Devil Dungeon.
• Unique Drops: Exclusive items like the Smoke Battlestaff and Pet Smoke Devil.
• Combat Style: Uses a typeless magical ranged attack with a max hit of 8.

Lore and Background

In the world of Gielinor, the Thermonuclear Smoke Devil is a smoky enigma. Confirmed in a Postbag from the Hedge letter to have an eye instead of a mouth, Thermy’s eerie design and ability to walk through other monsters add to its mystique. It’s a creature born from the depths of the Smoke Devil Dungeon, a place shrouded in haze and danger.

How to Reach the Thermonuclear Smoke Devil

Getting to Thermy is straightforward if you know the shortcuts. The Smoke Devil Dungeon lies south of Castle Wars, and preparation is key due to its smoky environment.

Fastest Travel Methods

Here are the best ways to reach the dungeon:

1. Fairy Ring (Code: BKP): Teleport using the BKP code and run northeast to the entrance.
2. Ring of Dueling: Teleport to Castle Wars, then head southwest to the dungeon.

Once inside, head northwest to find the crevice leading to Thermy’s chamber. Don’t forget a Slayer Helmet or Facemask—without it, the smoke will deal rapid damage and drain your stats.

Preparation Checklist

Before you face Thermy, ensure you have:

• Slayer Task: Assigned by a Slayer Master (e.g., Duradel or Konar).
• Protective Gear: Slayer Helmet, Facemask, or Gas Mask.
• Combat Supplies: Food, potions, and prayer restores.

Strategies for Defeating the Thermonuclear Smoke Devil

Thermy’s fight is mechanically simple but demands efficiency due to its fast attack speed (2 ticks, or 1.2 seconds). Its typeless magical ranged attack ignores protection prayers, so your strategy hinges on minimizing damage and maximizing output.

Melee Strategy: Step-Under Technique

The most popular method is the melee “step-under” technique, leveraging Thermy’s inability to attack when you’re directly beneath it.

• Gear: High slash weapons (e.g., Abyssal Whip, Dragon Scimitar), Bandos armor, Slayer Helmet.
• Method: Attack once, step under Thermy, wait a tick, then attack again. Repeat.
• Pros: Reduces damage taken, extends trips.
• Cons: Requires precise timing and attention.

Magic Strategy: Farcasting

For mages, farcasting with Ancient Magicks exploits Thermy’s longer attack range disadvantage.

• Gear: Trident of the Seas/Swamp, Ahrim’s robes, Ice spells (e.g., Ice Barrage).
• Method: Freeze Thermy with Ice spells, then attack from outside its 8-tile range.
• Pros: Safe and sustainable with Blood spells for healing.
• Cons: Higher supply cost (runes).

Redemption Prayer Method

For longer trips, use the Redemption prayer (requires 49 Prayer) to heal when your HP drops below 10%.

• Setup: 90+ Hitpoints, Prayer potions, Bloodbark armor for extra healing.
• Method: Tank hits, let Redemption trigger, restore Prayer, and repeat.
• Tip: Pair with a Prayer Regeneration Potion for efficiency.

Loot and Rewards from Thermonuclear Smoke Devil

Thermy’s loot table is a mixed bag—while its common drops are modest, the unique items make it worth the grind for many players.

Drop Table Highlights

Here’s a breakdown of Thermy’s notable drops (values based on April 2025 Grand Exchange prices):

Item	Drop Rate	Average Value
Smoke Battlestaff	1/512	~2M GP
Occult Necklace	1/350	~500K GP
Jar of Smoke	1/2,000	~1M GP
Pet Smoke Devil	1/3,000	Untradeable
Dragon Chainbody	1/2,000	~225K GP

Note: The average kill is worth around 23,602 GP, or 25,869 GP on a Konar task, per OSRS Wiki estimates.

Is It Worth Farming Thermy?

Compared to bosses like Zulrah or Vorkath, Thermy’s profit per hour (roughly 1-2M GP with 60-100 kills/hour) is lower. However, its simplicity and pet chance keep it relevant. For Ironmen, the Smoke Battlestaff and Occult Necklace are valuable upgrades.

Tips and Tricks for Mastering Thermy

To optimize your Thermonuclear Smoke Devil runs, consider these expert tips:

Efficiency Boosters

• Special Attacks: Use Dragon Claws or another high-damage spec weapon, then teleport to a POH to restore via an Ornate Rejuvenation Pool.
• Group Healing: Stack smaller Smoke Devils in the chamber and use Blood Barrage to heal off them.
• Menu Entry Swapper: Enable “shift-click walk here” for easier step-under timing.

Common Mistakes to Avoid

• No Facemask: Forgetting this will result in rapid damage and stat drains.
• Ignoring Attack Speed: Thermy’s 2-tick attacks can stack damage quickly if not mitigated.
• Overusing Supplies: Balance food and Prayer potions to avoid short trips.

With a kill rate of 60-100 per hour depending on gear and skill, Thermy is a solid choice for Slayer XP (around 30-50K/hour) and a shot at rare loot. Pair it with a good playlist, and you’ve got a rewarding grind ahead!

Ready to take on the Thermonuclear Smoke Devil in OSRS? This boss may not be the flashiest, but its unique drops and straightforward mechanics make it a staple for Slayer enthusiasts. Share your best Thermy stories or drop questions in the comments below—happy slaying!