Liberation of Undermine: Mythic Vexie and the Geargrinders Boss Strategy
Raid Composition
🛡 2 Tanks
💉 4 Healers
⚔ 14 DPS
Overview
Welcome to this comprehensive Mythic guide for Vexie and the Geargrinders — the opening boss of the Liberation of Undermine raid. Here you’ll find a full breakdown of Mythic-exclusive mechanics, along with strategic insights to help your raid team achieve victory.
Combat Style: Primarily Single-Target with cleave opportunities
Ideal Setup: 2 Tanks / 4 Healers / 14 DPS
Important Utility: Grips and knockbacks for the Intermission
Heroism/Bloodlust: Recommended use during Intermission
Quick Tips (Easy Mode)
Pick up Oil Canisters dropped by Bikers after they’re defeated
Use 2 Canisters to refuel and activate a Bike for boss-charging
Stop Support Rig from reaching the boss with crowd control during Intermission
Core Mechanics
Oil Canisters
When a Biker dies, they launch two Oil Canisters in nearby areas. These must be caught (soaked) by players. Failure to do so results in oil puddles forming on the ground. Canisters are used to refuel damaged Bikes — each Bike needs two to become functional. Once fueled, players can mount and drive them to collide with the boss.
⚠ Players who soak a Canister receive a debuff that increases damage taken by 500% from the next soak for one minute, preventing them from grabbing another.
Support Rig
A unique mechanic during Intermission. The Support Rig will spawn and move directly toward the boss. It emits a large radius that renders nearby Pit Mechanics immune to crowd control. This disables the raid’s ability to interrupt their healing casts, which can drastically prolong the encounter or even reset boss progress.
Thankfully, the Rig itself is vulnerable to all types of CC and will despawn at the end of the Intermission phase. Use displacement tools or stuns to keep it away from the boss.
Phase 1 Strategy
On Mythic difficulty, the encounter features two new mechanics—one during the main phase and one during the Intermission.
When a Biker is eliminated, it tosses two Oil Canisters into the area. These must be caught before they land, or else oil puddles will form, cluttering the arena. Players who catch these canisters are responsible for refueling damaged Bikes by interacting with them. A single Bike requires two canisters before it becomes operational.
To manage this efficiently, establish a left-to-right refueling order. Failing to organize this process may lead to Bikes being partially fueled, slowing down the ability to launch charges and potentially delaying damage phases. Additionally, oil puddles left from missed soaks can interfere with movement or block access to Bikes, increasing the risk of errors and time loss.
🔄 Important Rule: Stick to an agreed-upon fueling order to avoid unnecessary delays and random puddle placements.
Once a player picks up a Canister, they are afflicted with a debuff that increases the damage taken from any future soak attempts by 500% for one minute. This means you must rotate players to catch canisters. Coordination is critical to avoid overlap and ensure continuous fueling.
Missing a soak does not cause raid-wide damage, but oil puddles may complicate positioning and interfere with mechanics if left unchecked.
On Mythic, speed and precision are essential. The raid is essentially on a timer, as you need Bikes ready to charge the boss multiple times before energy thresholds are reached.
⏱ Goal: At least three stacks should be removed by the time the boss hits 50 energy.
Intermission Strategy
During the Intermission, a new mini-mechanic adds complexity to the phase. The Support Rig enters the field and starts moving toward the boss. It has a large aura that makes all Pit Mechanics inside it immune to crowd control. If this happens, the Pit Mechanics can’t be interrupted, and their healing casts will restore the boss’s health—potentially wiping your progress.
✅ Good News: The Rig itself can be completely crowd controlled. Although it has high health, killing it is unnecessary. Once the Intermission ends, it disappears automatically.
Recommended CC tools include:
Hard stuns
Displacement effects (e.g., Ring of Peace, Ursol’s Vortex)
Death Grip or other pull mechanics to reposition it
Keep the Support Rig far enough away from the boss so no Pit Mechanics enter its immunity radius. Preventing even one from casting is essential to avoid a huge setback in the encounter.
When the Intermission ends, resume your focus on catching canisters, fueling Bikes, and charging the boss. Repeat this rotation until victory.
💡 Note: If your raid is confident that the boss can be defeated before it reaches 100 energy, you may skip the Bike phase entirely at the end. Focus on direct damage instead and burn the boss down.