Act 2 is an audit of your deck
If your run dies in Act 2, the autopsy almost always reads the same way: the build was still a pile of good cards rather than an engine. The Hive, the insect-themed second act, jumps elite HP from Act 1's range straight to 145, 200 and multi-body totals, and it does this on purpose. Act 1 asks whether you picked good cards. Act 2 asks whether those cards form a machine that produces damage and Block every turn without your help. Those are different questions, and decks that squeaked through Act 1 on raw card quality get exposed here.
Two structural facts shape your routing. First, since v0.101 the game no longer spawns elites on floor 6, which gives you a small grace period at the start of the act: use those early floors to finish assembling, grab one or two card rewards, and only then decide how many elites you can afford. Second, the elite pool is only three encounters (Infested Prism, Entomancer, Decimillipede) but each one audits a different deck dimension, and our database tip for the act is stated plainly: have your engine online before Act 2, or skip elite paths.
The normal pool does not let you coast either. Tunneler at 87 HP and Ovicopter at 124 to 130 HP are stat-checks wearing normal-fight clothing; the Ovicopter in particular has more HP than several Act 1 bosses. The boss pool is Knowledge Demon, The Insatiable and Kaiser Crab, and it is genuinely the scariest trio in Early Access: one is widely considered the hardest boss in the game, one is a literal lose-on-zero timer, and one is a positioning puzzle with a 31-damage laser.
What should be true of your deck when the act starts? A scaling damage source that does not need you to draw it three times, a Block floor around 20 per turn for the damage turns you cannot dodge, some form of area damage for the swarm fights this act specializes in, and an answer, any answer, to statuses landing in your pile. If you are missing one of those four things, the act will find it and press on the bruise.
One more framing note for this guide: numbers below come from our verified v0.111 beta database, and The Hive is an act the developers have actively rebalanced during Early Access (Infested Prism was reworked as recently as v0.106). Where community sources disagree with patch notes, the value is flagged inline so you know what to double-check in game.
Tunneler: the 23-damage block check with a stun window
Tunneler is 87 HP and it runs a loop that quietly escalates. It bites for 13, then burrows, gaining 32 Block that never decays, and from below it strikes for 23 each turn. Read that again with Act 2 eyes: after the burrow, every single turn is a 23-damage attack for the rest of the fight, and the Block it gained is permanent. Fights that drag become arithmetic problems you eventually lose.
The database gives you the out, and it is the single most important sentence for this fight: breaking all of its Block stuns it for a turn. That means the fight has a deliberate rhythm of two phases. In the damage phase you block 23 and chip. In the window phase, right after it burrows, you dump burst damage to crack through the full 32 Block in one turn, collect the free stun turn, and use that turn for whatever you want: more damage, powers, healing, setting up, or just an easy full-block turn that costs you nothing.
Holding burst for the window is the discipline. Decks that spend everything on the bite turn arrive at the burrow with nothing left and never trigger the stun once; decks that bank a hand of damage every cycle get a free turn per loop, which compounds enormously over a long fight. If your deck has zero burst potential, the alternative line is honest attrition: block 23 every turn, attack with the leftovers, and accept a slow win. That line works, but it is where most of the silent HP bleed in Act 2 comes from.
Character notes. Defect has the easiest time here by a wide margin, since orb damage ignores the equation entirely: Lightning evocations are flat damage that does not care about the Tunneler's Block total, and Tempest into Dualcast cracks the shell almost on cue. Ironclad wants Body Slam lines, because damage equal to your Block converts a defensive turn into shell-breaking damage. Silent and Necrobinder can lean on Poison and Doom, both of which tick straight through Block. Regent is the most timing-dependent, saving Star banks for the burrow turn so Astral Pulse or Seven Stars lands inside the window.
One planning note for the whole act: the 23-per-turn strike is the number your Block floor has to cover from mid-act onward. If you look at your deck and cannot find 23 Block on a generic turn, Tunneler will not be the only fight that tells you so.
Ovicopter: three eggs, two turns, one AoE window
Ovicopter is a 124 to 130 HP normal fight that plays like a scripted encounter, and it wins more often than its normal-fight label suggests because the timer is tight. It spawns 3 tough eggs that hatch into larvae within 1 to 2 turns, and once the board is live it settles into a loop of a 16-damage slam and a Softening strike that applies 2 Vulnerable. The 16 slam is manageable. The Softening is not, because Vulnerable turns every future slam and every larvae hit into a tax on your Block.
Your job in the opening turns is unambiguous: pop the eggs before they hatch. Every egg that hatches converts a static target into an acting body that damages you every turn and multiplies the AoE requirement later. The database tip is direct: AoE is at a premium here. If your deck can hit three eggs at once in the 1 to 2 turn window, the fight collapses into a simple 130 HP race against a 16-damage loop. If it cannot, you are playing a four-body fight where your single-target damage gets spread thin and Softening stacks up.
This is the fight to scout your deck for before the act starts, not during it. Whirlwind on Ironclad, Astral Pulse on Regent, Tempest on Defect, Noxious Fumes on Silent (Poison ticking on all bodies is exactly the multi-target pressure eggs hate), and End of Days on Necrobinder, which our card database describes as massive AoE Doom that executes at threshold: that is an egg-board deleting card. Relics matter too: Festive Popper dealing 9 to all enemies at combat start softens the whole clutch before your first play, and Mercury Hourglass chips every body at every turn start.
When eggs do hatch, change targets rather than panicking. The Ovicopter itself keeps looping slam and Softening while larvae add chip damage; killing larvae first cleans the board but leaves the Vulnerable source alive, while killing the parent stops Softening but leaves bodies swinging. The general rule from how this fight scores out: clean the larvae with incidental AoE and focus the parent, unless your hand happens to delete a larva for free. And if you enter this fight already carrying Vulnerable from an earlier scrape, respect the Softening turn hard, because stacked Vulnerable plus a 16 slam plus larvae is how a normal fight ends a run.
Gremlin Horn deserves a special mention: gaining 1 energy and 1 draw whenever an enemy dies turns egg-hatch boards into fuel, and it is one of the best relic pickups in the act precisely because The Hive keeps manufacturing multi-body fights.
Infested Prism: the 200 HP gatekeeper
Infested Prism is 200 HP, which is more than every Act 1 boss except the Ceremonial Beast, and it occupies the elite slot. Our database calls it exactly what it is: a gatekeeper that checks whether your build came online. There is no clever trap in its entry as we have it documented; the fight is a raw throughput test, 200 HP of wall standing between you and the relic drop, and the question is whether your deck can sustain meaningful damage and defense at the same time for the six or more turns that wall requires.
Honest data note, because this guide commits to version accuracy: Infested Prism was reworked in v0.106, and our v0.111 database carries its current HP but only a thin mechanical description beyond that. Treat any detailed pattern list for this elite you read elsewhere as provisional until verified in game, including ours. What we can state firmly is the strategic frame that has not changed across its versions: it is a stat check, and stat checks are won before the fight starts, during the acts' shops, campfires and card rewards.
So how do you actually beat a stat check? You arrive overprepared. Concretely: upgrade your scaling card at the campfire before the elite rather than resting at full HP (our mistakes list flags only-resting as one of the most common errors in the game), spend potions here instead of hoarding them for the boss (Strength Potion on turn one of a 200 HP fight is worth far more than a hypothetical later use, and Block Potion converts one bad intent into a free turn), and make sure whatever your engine's key card is, you have drawn it and played it by turn two.
Deck-shape advice for the throughput test. Front-loaded decks struggle most, because 200 HP outlasts a hand of good commons; you want something that compounds: Poison counts with Catalyst doubling, Strength stacking into multi-hit attacks, Star banks releasing as Seven Stars, Frost-fed Block that grows as the fight extends. The act's Amalgamator event, which replaces two starter Defends or Strikes with an upgraded Ultimate version, is nearly free value before this fight if your path offers it, and two card removals quietly make every draw closer to your engine.
And the skip line, stated without embarrassment: if your answer to can I kill 200 HP while blocking is a shrug, path around this elite. The relic is real and skipping elites all run is how you arrive at the Act 3 bosses underpowered, but feeding a 200 HP elite an undercooked deck costs 30 or more HP and usually the run anyway. Take the campfire, take the shop, come back next elite.
Entomancer and Decimillipede: splitting enemies done right
The Hive is the act of enemies that multiply, and the two remaining elites teach the same lesson from opposite ends: raw spawning versus structural splitting. Entomancer, 145 HP, summons bees all fight long, so the board keeps growing no matter how well you sweep. The database gives two lines and both are real: bring AoE, or burn the caster down directly and let the summons stand around leaderless. The second line is often better than it looks, because killing the Entomancer removes the faucet, and existing bees are a finite problem your Block can absorb while you close out the fight.
Decimillipede is the more interesting and more misread elite. It is three segments, 40 to 46 HP each per current patch notes, acting independently on their own turns. The trap: when a segment dies while the others live, it Reattaches at 25 HP. AoE, the instinctive answer to a multi-body enemy, wounds all three segments simultaneously, triggers reattachments, and can actively prolong the fight while your hand empties. Focus fire is not merely good here, it is the mechanic: concentrate one segment at a time, let each die while the others stay healthy enough not to chain-trigger, and once two segments are permanently down the pressure drops sharply, which is precisely what our database tip observes.
Data caveat worth knowing before you plan around exact numbers: our file flags the per-segment HP as coming from patch notes while the wiki infobox still shows 42 to 48 per segment. The 40 to 46 figure is the one we trust for v0.111, but the takeaway does not change between the two: segments are small, the reattach rule is the fight, and single-target damage is the answer.
How to think about split mechanics generally, because Act 3 will retest the idea with worse numbers: ask what the split costs the enemy and what it costs you. Decimillipede's split costs you tempo if you spread damage, so you refuse to spread. Entomancer's spawning costs the enemy nothing, so you either match it with sustained AoE (Noxious Fumes ticking on every bee, Mercury Hourglass, Whirlwind with Strength behind it) or you cut the head off and starve the board. Kaiser Crab at the act's end splits the boss into two claws with a revenge mechanic, and the discipline is the same one more time: commit to one target fully instead of shaving both.
Practical per-character lines for the millipede: Silent and Necrobinder should ignore their DoT instincts here or apply them to one segment only, since spread Poison across three bodies feeds reattach windows; Ironclad's single big hits are ideal; Defect should evoke into one segment, not split orbs across the board; Regent's banked Star burst dropped on one segment at full health kills it outright, which is exactly the shape of play the fight rewards.
Kaiser Crab: surround math and the revenge window
Kaiser Crab is one boss expressed as two bodies: 209 HP on one part and 199 on the other, with the Surrounded mechanic binding them. Because you are surrounded, hits from the claw you are facing away from deal 50 percent more damage to you. Facing is a real decision every turn of this fight: whichever claw you turn your attention toward, the other one hits you harder, so the intent you can least afford to eat should be the one you face.
The lethal move is the Rocket claw's Laser at 31 damage, comfortably the biggest single hit in the act, and bigger still if you happen to be facing away from it when it charges. Our database tip names the plan outright: focus the Rocket claw first. Killing the laser removes the only attack in the fight that threatens to one-shot a healthy character, and after that the remaining claw, whatever it does, is a blockable nuisance you can grind down at your own pace.
Now the part that ends runs. When one claw dies, the other gains Strength and 99 Block as a revenge trigger. That 99 Block means your damage is bouncing off for roughly the next turn or two no matter what you play, and the Strength gain means whatever it does next hurts more. The counter is timing: kill both claws within one to two turns of each other so the revenge window has nothing left to protect. If you take the Rocket down and then need five turns to break a 99 Block wall on the survivor, you experience the worst stretch of this fight with a buffed boss swinging at you. Bank your burst, drop claw one, then immediately unload into claw two before the wall matters.
Data flag, in the spirit of this guide's accuracy policy: the revenge Strength value is actively disputed between sources. Patch notes say 6 Strength; the wiki infobox still says 5. Our file records both and marks the value uncertain, so plan for 6 and be pleasantly surprised by 5 rather than the reverse.
AoE has a special role here that is worth spelling out: area damage hits both claws. That does double duty in a fight where you want both bodies low simultaneously, so a Whirlwind, Astral Pulse or Tempest turn is effectively two attacks for one card, and it sets up the clean finish where both claws die inside the same revenge window. Poison lines work the same way, ticking on both bodies at once, and Catalyst doubling on the Rocket claw accelerates the first kill. Regent should note the reverse temptation: Seven Stars' 49 AoE is glorious here, but bank it for the post-first-kill window rather than opening with it into two full-health claws.
Knowledge Demon: the hardest boss in Early Access
Knowledge Demon sits at 321-plus HP and our database does not hedge about its reputation: widely the hardest boss. Its kit is a stack of compounding problems. Each round it forces a permanent debuff choice on you, choosing between things like 6 damage per turn, minus 1 draw, and later in the fight card and energy caps. On top of the debuff ladder it self-heals and gains Strength permanently. There is no phase you can skip and no single trick that dodges the kit; the fight is designed to make every turn slightly worse than the last until you cannot function.
The strategic headline is a race. Every turn you spend setting up is a turn the debuff ladder climbs and the Demon's Strength accumulates, so this is the boss where aggressive, honest DPS beats careful defensive play. Our database tip adds a specific tech line: punish its multi-hit turns with Thorns or Flame Barrier-style effects, damage reflection that turns its offense into your output. If your deck or relic pool can mount any form of retaliation damage, this is the fight it was waiting for.
Think about the debuff choices as a draft against yourself. You will be picking your own poison several times, so decide your order before the fight: which debuff can your specific deck absorb most cheaply? A deck that plays few cards per turn barely feels a card cap. A deck that blocks 20-plus per turn can eat 6 damage per turn and heal or shrug it off. A deck with heavy draw filtering (Prophesize, Acrobatics lines, Compile Driver orb draws) cares least about minus 1 draw. Know which one you are before the menu appears, because panic-picking under a 300 HP boss is how you stack the debuff you can least afford.
Escalation math also argues for potion timing here more than any other fight. The self-healing means a stalled mid-fight wastes your resources while it regrows, so burn Strength Potions, Fire Potions and Energy Potions early to force the HP bar down through the first debuff rounds, when your deck still works at full capacity. Fairy in a Bottle as insurance is arguably at its best against this boss specifically, since the difference between a wipe and a win is often one extra turn of damage.
Per-character notes: Ironclad's Strength scaling is the cleanest race line, and his max HP pool absorbs the attrition debuffs. Silent Poison races poorly into self-healing unless Catalyst doubling is online, so have the doubling ready before the HP bar stalls. Regent wants Star banking finished in round one and released aggressively. Defect's Dark orb burst turns and Necrobinder Doom stacks both execute thresholds that self-heal cannot out-tick, with the v0.108 resolution-order caveat that Doom executes at end of turn now.
The Insatiable: a countdown you cannot block
The Insatiable is 321 HP and carries the single most unusual lose condition in Early Access: a Sandpit death timer that starts at 4. When the timer reaches zero, you lose. Not you take damage, not the boss enrages: you lose, the run ends, regardless of your HP total and regardless of any Block, Intangible or fairy-potion insurance you are holding. There is no defensive answer to this boss at all, which makes it the purest tempo check in the game.
The mechanic that keeps the fight winnable is Frantic Escape. Escape cards get added to your deck during the fight, and each one played buys one more turn on the Sandpit timer. Our database tip compresses the entire strategy into three instructions: always play Escape cards, never exhaust cards carelessly, spend everything. Expand that into fight rules: every turn, before anything else, confirm you played the Escape card you drew; never spend an effect that exhausts your hand or random cards, because an Escape burned out of existence is a turn you cannot buy back; and treat resources as already spent, because gold-on-death is worth nothing and an unplayed potion cannot extend a timer.
The tension is that you are doing two jobs on one energy bar. Buying turns with Escape cards costs tempo you also need for killing a 321 HP boss, and every turn you spend only surviving is a turn the boss spends alive. That makes cheap damage king: 0-cost attacks, Shivs, orb passives ticking without input, Osty attacking on command via free Poke effects, Stars cashed through Alignment into efficient bursts. Decks that need four-energy setup turns to deal 20 damage will feel this timer in their chest.
Careless exhaust deserves one more warning because it is the silent killer. Effects that exhaust cards for value, which are excellent everywhere else in the game, are actively dangerous here: if an exhaust effect eats an Escape card you had not played yet, you have converted your own life expectancy into minor value. Check what an exhaust effect will consume before playing it, every single time, and if you cannot verify it, hold it.
Where the act's systems feed into this fight: the Amalgamator event removing two starters improves Escape draw density slightly, and any deck-thinning you did all run pays out here, since a smaller deck means Escape cards cycle back to your hand faster. The Insatiable is also the best argument in the act for the community's deck-thinning consensus: fewer dead cards means more turns per life. If your routing offered a shop removal earlier in the act and you skipped it, this is the boss that makes you think about it again.
The five typical Act 2 deaths and how to prevent each
Pulling the act together into the failure modes we see kill runs, so you can check your own deck against them before the map does it for you.
Death one: entering the act with a pile instead of an engine. The Infested Prism fight is usually where this one happens, 200 HP of wall against a deck that peaks at 15 damage per turn. Prevention is Act 1 discipline: by the end of the first act you want a card or two that compounds each fight (a scaling power, a Poison engine, Star banking, orb passives), not just five good commons. If you did not get there, path Act 2's early floors to shops and card rewards before any elite.
Death two: no AoE against the swarm act. Entomancer's endless bees, Ovicopter's egg clutch, Kaiser Crab's two bodies: The Hive manufactures multi-enemy pressure constantly, and single-target decks bleed out of HP a few points at a time. Prevention: own one real AoE card by mid-act, or own relics that substitute for one (Festive Popper, Mercury Hourglass), or build so much single-target damage that you delete spawners before boards form.
Death three: split-mechanic misplay. AoE-ing a Decimillipede into constant Reattaches, or shaving both Kaiser claws until both sit at half and the revenge buffs land while both live. Prevention is target commitment: one body at a time, all the way dead, always, in this act specifically.
Death four: the 31-damage Laser and the 23-damage burrow strike catching a deck with a 12-Block floor. Act 2's damage numbers assume your Block grew after Act 1. Prevention: upgrade a Block card at a campfire if your floor feels thin, keep Block Potion-class effects for telegraphed big intents (the game shows you the intent, the mistake list reminds you everything is telegraphed), and respect that facing matters against Kaiser Crab so the laser never lands at 150 percent.
Death five: resource hoarding. Saving potions for a boss you never reach, resting at campfires when 40 HP would have survived the next fight anyway, refusing the Amalgamator's free deck improvement. Prevention is the mindset shift our mistakes page keeps repeating: HP above 1 is spare, potion slots are only three, and upgrades often outvalue heals. The Insatiable, where unspent resources literally translate to losing on a timer, is the act's final exam in spending.
One routing note to close: Wongo's, the act's shop event, punishes refusing (it downgrades a card), so never refuse; and the Potion Courier event is free value to pick up in Act 2 even though its payoff, the hidden Merchant fight, belongs to Act 3. Small edges, but Act 2 is exactly the act where small edges decide whether Act 3 is a victory lap or a wall.