Electron-Drill XR-9, Rogue Automaton: how to beat

Electron-Drill XR-9, Rogue Automaton — dungeon “Gearnid - The Flooded Gnomegrad”, level 34. The deck: phases, turn cycle, damage and healing by mode, cold,…

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Dungeon Gearnid - The Flooded Gnomegrad, boss 3 of 5, level 34.

The boss plays its own deck: every turn it plays the next line of its phase’s cycle, with no randomness. Learn the cycle and you know what is coming. The numbers on this page are the same as in the card tooltip in combat: before Hardiness and Defender’s Stance. Mechanics in detail — Boss mechanics.

In short

Modes: Heroic (at level 60), Normal (at the place’s level, 29–38), Keystone +10 (Mythic+, at level 60).
2 phases, 5 cards in the deck. Schools: ⚡ Storm 3, 🔥 Fire 1, ⚔ Physical 1.
“Frost on the Casing” cold: every enemy turn, everyone through shields — heroic 440, keystone +10 360 to each before Hardiness. No cold in normal mode.
“Error, Repeating” test strike — on boss turns 8 and 16: heroic 7,000, keystone +10 8,000; 40% weaker with a defensive card on yourself.
The heaviest hit is “Error, Repeating”: heroic 7,000, keystone +10 8,000.

Phases and turn cycle

The phase changes with the boss’s Health. In each phase the boss goes round its own cycle: at the end it starts again. The boss’s next turn shows on its portrait.

1. “On Guard” — from the start of the fight

Down to 30%: a spark every 2–3 turns.

Cycle step	What the boss plays
1	⚔ Manipulator
2	⚔ Manipulator + ⚡ The Spark Runs
3	⚔ Manipulator + ⚡ Grate
4	⚔ Manipulator
5	⚡ The Spark Runs

2. “Overheating” — below 30% Health

Below 30%: open, sparks more often.

On entering the phase the boss plays at once: 🔥 Overheating.

Cycle step	What the boss plays
1	⚔ Manipulator + ⚡ The Spark Runs
2	⚔ Manipulator + ⚡ Grate
3	⚡ The Spark Runs

The “Error, Repeating” test strike is not part of the cycle: the boss announces it on its turns 7 and 15 and hits on turns 8 and 16.

Cards and numbers

The number is what a hit takes before Hardiness (through shields — from Health only), how much the boss heals itself, the shield it puts up, a minion’s Health. A dash means the card is not in that mode or has no number. Keystone: +10 numbers; hits are the same from +7 to +9 and weaker per level below +7.

Card	What it does	Heroic	Normal	Keystone +10	How to answer
⚡ Error, Repeating · Storm, test strike	A test strike on whoever holds the boss’s attention (usually the tank). The boss announces it on its own, outside the cycle, and hits on its 8th and 16th turn; one turn before, there is a countdown on the portrait and a warning above your hand. The target plays a defensive card on themselves before the hit — it is 40% weaker. Not in normal mode. Through shields.	7,000 · with a defensive card 4,200	—	8,000 · with a defensive card 4,800	Test strike, one turn of warning. The tank plays a defensive card, the healer tops him up in advance.
⚔ Manipulator · Physical, hit	A hit on whoever holds the boss’s attention (usually the tank).	2,350	500	4,100	A plain hit.
⚡ The Spark Runs · Storm, chain hit	The hit jumps across 3 fighters, each next one 25% stronger. Shields hold half.	705 → 881 → 1,058	100 → 125 → 150	820 → 1,025 → 1,230	Jumps across three, stronger on each, half through shields. Keep everyone above half.
⚡ Grate · Storm, stun	Stuns a damage dealer or the healer (past the tank) for 1 turn.	—	—	—	The target is stunned for a turn.
🔥 Overheating · Fire, opening: more damage to the boss	The boss is open: damage to it ×1.2 for 99 turns.	—	—	—	Open: +20% damage until the fight ends.

“Frost on the Casing” cold

Hot inside, frost outside. We do not recommend hugging him.

Heroic: 440 to each per enemy turn, before Hardiness.
Keystone +10: 360 to each per enemy turn, before Hardiness.
Hits every fighter in the party through shields; Hardiness reduces it — better gear takes less.
The answer is healing every turn: shields do not stop cold. Healer cards do it best — they heal Health only.
No cold in normal mode.

Test strike

“Error, Repeating” — on boss turns 8 and 16, through shields, on whoever holds the boss’s attention (usually the tank). On heroic, while the party’s tank is alive, it goes to the tank. Not in normal mode.
Heroic: 7,000 before Hardiness; 4,200 if the target answered with a defensive card.
Keystone +10: 8,000 before Hardiness; 4,800 if the target answered with a defensive card.
One turn before the hit there is a countdown on the portrait and a warning above your hand. The target plays a defensive card on themselves: a self-shield, damage reduction or “cannot be killed”. A card someone else plays on the target does not count.

Enrage

Heroic: from party turn 40, every boss turn is 4% stronger, and it stacks.
Normal: as before — if the fight drags on past its expected length, the boss hits harder every turn.
Keystone +10: as before — if the fight drags on past its expected length, the boss hits harder every turn.

Roles

Tank

The “Error, Repeating” test strike lands on the boss’s 8th and 16th turn (heroic and keystone +10). One turn before, play a defensive card on yourself — a self-shield, damage reduction or “cannot be killed”: the hit becomes 40% weaker. Keep such a card in hand for those turns.
Shields do not stop this hit: the healer tops up your Health before it.
“Manipulator” hits you. Keep Taunt on rhythm: while the boss hits the tank, the rest stay whole. The heaviest is “Manipulator” (“On Guard” phase, cycle step 1).
Do not fall: on heroic, mythic and in keystones, without a living tank the boss’s hits on its focus go through shields. A resident can be the tank too.

Healer

“Frost on the Casing” cold hits everyone through shields every enemy turn: heroic — 440, keystone +10 — 360 to each before Hardiness. Heal everyone every turn; healer cards do it best — they heal Health only.
“The Spark Runs” hits everyone. Before that turn, get everyone above half Health; it goes half through shields: shields hold half, the rest hits Health.

Damage dealers

“Overheating”: the boss is open and takes more damage — save your strong cards for that turn.
“Grate” hits your cards and crystals: do not hoard everything for one turn.
Do not drag it out: heroic — enrage from turn 40.

The heaviest hits

“Error, Repeating” — test strike, through shields.
“Manipulator” — on the tank; “On Guard” phase, cycle step 1.
“The Spark Runs” — on everyone, half through shields; “On Guard” phase, cycle step 2.

Loot

All of the boss’s loot with rough drop chances is in the item atlas; rules and items by boss are on the Gearnid - The Flooded Gnomegrad page.

Previous boss — Vix Rattlespine, Menagerie Master. Next boss — Chief Mechanist Crank Smokelove.

All bosses of the place — Gearnid - The Flooded Gnomegrad. Rules of a fight against a boss with a deck — How to beat: every boss.