What Ascension is and what a Glory clear unlocks
You beat the floor 48 boss, the run ends, and the next time you pick that character a small flame icon appears next to the run setup. That flame is Ascension, and it is the entire endgame structure of Slay the Spire 2 Early Access as of v0.111 beta. It is also shorter than you expect if you played the first game: ten levels, not twenty. The ceiling is A10, and each level adds one cumulative modifier on top of everything before it, so A10 runs carry all ten effects at once.
The unlock rule is per character. Defeating any Act 3 boss with a character unlocks Ascension 1 for that character, and clearing Act 3 at a given level unlocks the next one. Nothing carries between characters: a maxed Ironclad tells the game nothing about your Silent. Two freedoms matter once you are on the ladder. You can select any level you have already unlocked, so farming A1 unlock speedruns or dropping from A9 to A4 for a relaxed evening are both real options, and you can see exactly which modifiers are active before you commit, since the game lists them on the selection screen.
The system has churned quite a bit during Early Access, which is worth knowing when you read older guides. The original six levels shipped in the pre-Early-Access v0.32 builds, per-character unlocks arrived in v0.40, and separate multiplayer tracking in v0.50. Ascension 1 was reworked from buffed bosses to elite spawning in v0.62, A2 healing was buffed from 75 to 80 percent of missing HP in v0.83, and A10 went through three designs, Villainy in v0.76, Ascender's Scorn in v0.87, and finally Double Boss in v0.90. The v0.92 pre-release patch reordered the middle of the ladder into the current Scarcity, Tough, Deadly arrangement, and v0.104 deliberately tuned the low levels easier and the high levels harder. If a guide dated before April 2026 tells you A6 is fewer rest sites, it is simply describing a different game.
One more framing point before the level list. Ascension in STS2 was compressed from STS1's twenty levels, with the three deadlier-enemies tiers and three tougher-enemies tiers folded into single steps and several modifiers dropped entirely. The practical consequence is that each STS2 level is a bigger deal than one STS1 level, and the jump between adjacent levels, especially 8 to 9, lands harder. The rest of this guide walks the ladder bottom to top, then covers the multiplayer track and a concrete climbing plan.
A1 through A5: more elites, thinner heals, thinner gold, one less slot, the Bane
Ascension 1, Swarming Elites, spawns roughly 60 percent more elites across your maps. This is the level that rewires routing, not combat. Elites are the best fights in the game, they drop relics, and the relic economy is what carries mid-tier decks into Glory, so A1 is not really a punishment, it is a forced engagement with the part of the map most beginners dodge. In the Act 1 variants that means more exposure to Bygone Effigy (127 HP), Byrdonis (91) and Phrog Parasite (61) in Overgrowth, or Skulking Colony (79), Terror Eel (140) and the multi-body Phantasmal Gardener in Underdocks. Path to elites when your deck has one or two answers, and path away when it does not.
Ascension 2, Weary Traveler, cuts every Ancient heal from 100 to 80 percent of missing HP, and this includes Neow at the start of the run. Since Ancients heal you at every act transition, the tax compounds: you enter the Hive and Glory progressively less healthy across a whole run, and boss fights now cost real, permanent HP. Max HP sources such as Nutritious Oyster (plus 11) or Stone Humidifier (plus 5 per rest) quietly gain value, and the old habit of walking into bosses at 30 percent HP stops being free.
Ascension 3, Poverty, cuts gold from enemies and treasure chests by 25 percent. Boss payouts drop from 100 to 75 gold. The economy tightens exactly where removal and shop relics live, so event gold, Spoils Map style quest rewards and hoarding for the Act 3 shop all matter more. Treat every shop visit as a budget meeting: you will see less money overall, so pre-decide whether this run's gold is assigned to removals, a specific relic or potions.
Ascension 4, Tight Belt, removes one potion slot, taking you from three to two. The cost is not storage, it is flexibility: you can no longer hold block, burst and insurance simultaneously. Potion discipline becomes a real skill. Drink the potions that save HP in normal fights, keep at most one slot for the answer you know the boss demands, and stop walking into floor 48 with two full potions you never cast.
Ascension 5 drops the Ascender's Bane into your deck for the entire run: Unplayable, Ethereal, and Eternal, which means it cannot be removed or transformed by anything. If you draw it and end your turn with it in hand, it Exhausts for that fight, so the realistic cost is one dead draw a shuffle plus the deck slot it occupies. The answer is the same as always: a thinner deck shuffles past the Bane faster, and any strategy built on drawing your whole deck needs to account for a card that does nothing.
A6 Inflation: the removal tax that rewrote deck thinning
Ascension 6 is the level Mega Crit rebuilt mid-Early-Access, and its current form is a direct nerf to the strongest generic strategy in the game. Inflation makes card removal at the Merchant cost 100 gold for the first card instead of 75, and every subsequent removal costs 50 more instead of 25. It replaced Gloom (fewer rest sites) in the v0.102 beta patch of April 2, 2026 and reached the default main branch in Major Update 1, v0.103.2, two weeks later, which is exactly the milestone our patch log records for it.
Run the arithmetic to feel the difference. Four removals under the old pricing cost 75, 100, 125 and 150 gold, 450 total. Under Inflation the same four cost 100, 150, 200 and 250, a total of 700. The second and third removal, the ones thin decks actually want, nearly double in price. Since removing starter Strikes and Defends is usually the best gold sink in the game, A6 does not add a new mechanic, it reprices the backbone of every consistent deck.
The response is to move removal off the merchant entirely. The Ancient boon pools are full of discounted thinning: Neow offers Precise Scissors (remove 1) and Precarious Shears (remove 2, lose 16 HP); Darv's shared pool carries Empty Cage (remove 2); Tezcatara's Biiig Hug removes 4 cards at the cost of a Soot per shuffle; Pael's Tooth removes 5 and feeds them back upgraded over time. Transformation counts double here, since a transformed Strike stops being a Strike: New Leaf, Leafy Poultice, Astrolabe and the evergreen Pandora's Box all sidestep the gold cost. Events that remove or transform become high-priority picks rather than gambles.
Shop relic prices were cut by 25 gold in the same Major Update 1 that shipped Inflation, so the merchant is not dead, just rebalanced: relics got cheaper while removals got pricier, which pushes gold toward relics and event-based thinning. Note also that Afflictions, the sequel's replacement for Curses, latch onto cards you already own and cannot be removed at shops at all, so Inflation only touches the cards you chose to cut.
The strategic summary of A6: plan your thinning before you need it. If your route banks on trimming three cards at the floor 44 shop, the 450 gold that plan used to require is now 700, and no run in this economy reliably holds that much alongside a relic purchase. Take the free removals when the Ancients offer them, keep event removals on your radar from floor 1, and treat merchant removal as the emergency option it has become.
A7 Scarcity: drafting when rares and upgrades halve
Ascension 7, Scarcity, makes rare and upgraded cards appear half as often across combat rewards and merchant stock simultaneously. It is the quietest of the ten levels and the one that most changes what your deck looks like at floor 48, because it attacks the two levers that make mid-game decks spike: rare bombs and pre-upgraded commons.
The first adjustment is pick order. Commons and uncommons are now your diet, so evaluate them like it. A common that fills a hole in your curve outdrafts a rare that wins a fight you already win, and uncommon archetype pieces, the glue cards every build actually runs on, become the picks you plan around. When a rare does appear, it competes for the same slot as always, but you see maybe half as many of them, so the cost of passing one rises. The mistake to avoid is rare-worship: passing a solid uncommon for a 5 percent chance the next reward contains the rare you want.
The second adjustment is the campfire. Upgraded cards appearing half as often means your own Smith upgrades carry more relative weight, because the game hands out fewer of them for free. The rest-versus-smith calculus tips further toward smithing than most players assume, especially for cards whose upgrade changes their role rather than their numbers: costs dropping from 2 to 1, draws going from 2 to 3, powers doubling. On A7 and above, a run that smiths its engine cards on schedule simply has a better deck than one that heals.
The third adjustment is relic pricing, again. Rarity-cutting tools jump in value: Driftwood (reroll each card reward once) converts bad offers into second chances, Hefty Tablet (choose 1 of 3 rares, at the cost of an Injury in your deck) becomes one of the strongest Neow boons precisely because it buys the rarity A7 deleted, and Glass Eye injects a flat 2 common, 2 uncommon, 1 rare package into your pool. If you see any of these in an Ancient draft, they are picking up exactly what the level removed.
One caution for ladder climbers: A7 changes deck shape, not fight math, so runs lost at this level are usually lost to drafting habits rather than to the modifier itself. If your A7 win rate craters while your A6 rate holds, audit your picks, not your pathing. The tell is decks full of unupgraded commons dying in Act 3 with no plan, which is Scarcity working exactly as designed.
A8 and A9: per-enemy tuning, not flat percentages
The last two stat levels look bland on the selection screen. Tough Enemies, all enemies have more HP. Deadly Enemies, all enemies deal more damage. What makes them interesting is how they are implemented: instead of STS1's flat plus 25 and plus 50 percent modifiers, STS2 tunes each enemy individually, so the actual deltas vary by creature, and the official wiki records them per boss.
The verified Act 3 examples show the scale. The Queen goes from 400 to 419 HP at A8 and her Torch Head Amalgam from 199 to 211. Test Subject's three bodies rise from 100, 200 and 300 to 111, 212 and 313. Aeonglass climbs from 512 to 535. Those are single-digit percentage moves, and community-aggregated data covering all 112 enemies in the game (single-source, treat as approximate) says about 101 enemies gain HP at A8 with a median increase around 5.6 percent, most landing between 3 and 9 percent.
A9 is where the ladder bites, because damage breakpoints cross block thresholds. The Queen's Off with Your Head goes from 3 hits of 5 to 4 hits of 5, and Execution from 15 to 18; her Amalgam's Strong Tackle jumps from 26 to 32. Aeonglass's Ebb rises from 22 to 26, Eye Lasers from 11x2 to 12x2, and Increasing Intensity escalates from 1 to 2 Withers per cast and from 2+X to 3+X Strength. Test Subject's Enrage goes from 2 to 3 Strength per skill, Bite from 20 to 22, Multi-Claw from 10 to 11 per hit, and Burning Growl from 3 Burn plus 2 Strength to 5 Burn plus 3 Strength. The community data set says 98 enemies hit harder at A9. None of these numbers look dramatic in isolation. Together they delete the margin by which a 20-block turn covered a 19-damage intent.
The practical consequence is that block math must be redone, not estimated. On A8 and below, you could eyeball whether a block card covered an intent; past A9, look up the enemy's actual A9 numbers in the bestiary (added in v0.105) and count. Hallway fights are where this lands hardest, because STS2's elites already hit hard: Mecha Knight sits at 300 HP in Glory, Soul Nexus at 234, and a few extra damage per swing across a five-cycle fight is a full heal's worth of HP.
Two mental models help. First, A8 mostly extends fights, which favors scaling decks and punishes front-loaded ones that run out of gas. Second, A9 mostly punishes leaks, which favors consistent block, Max HP banking and potion usage over greed. When both stack, the game stops forgiving the third leak of a fight, which is the entire reputation of the next level up the ladder.
Why the community calls A9 the real wall
Ask r/slaythespire which Ascension level is hardest in STS2 and the answer recurs across separate threads: A9, not A10. That is community consensus rather than a documented fact, but the reasoning is structural. A10's double boss is a finale problem you can plan for across an entire run, while A9's damage increase applies to every fight from floor 1, including the hallway fights that used to be free. The wall is not the boss. The wall is that the middle of every act stops subsidizing you.
Concretely, A9 breaks runs in three places. First, Act 1 elites: a fight like Terror Eel at 140 HP or Bygone Effigy at 127 with buffed damage output now punishes the two or three turns your deck spends setting up, and the elite you pathed into at 80 percent HP kills you instead of costing 25. Second, Act 2 tempo: the Hive's elite HP jumps (Infested Prism at 200, Entomancer at 145) were already the litmus test for unfinished engines, and A9's damage makes slow starts lethal rather than costly. Third, Glory attrition: five elites and 600-plus HP bosses with A9 numbers delete the slack that let sloppy decks win at A8.
The adjustments that matter are unglamorous. Max HP is the resource A9 actually taxes, so banking it early (Nutritious Oyster, Stone Humidifier, event HP, cooking with a Meat Cleaver) converts to real survivability. Potion discipline stops being optional: with two slots on A4-plus, casting the block potion on the telegraphed 30-damage turn is worth more than any hoarded finisher. Elite selectivity becomes a skill: fight the elites your deck beats, skip the ones it does not, and accept slightly fewer relics in exchange for arriving at the boss alive. And deck thinning, cheap before A6 and pricey after, becomes non-negotiable, because a deck that draws its block card reliably survives multi-hit turns that kill a bloated deck.
Character choice also colors the wall, though community opinion genuinely conflicts here. One AMA-style thread from a player who cleared A10 on every character called the Regent the hardest climb; a later ranking thread puts the Necrobinder and Silent at the top with the Ironclad unanimously easiest. Both are community-reported takes, and the honest reading is that the wall moves depending on whether your fundamentals are tempo (favoring Ironclad) or engine play (favoring the orb-heavy Defect).
The encouraging number, also community-reported: multiple players describe STS2 at A10 as notably easier than STS1 at A20, with one finishing the full A10 sweep across all characters in roughly 57 hours. The wall is real, but it is a wall with a top.
A10 Double Boss: the gauntlet that ends the ladder
Ascension 10 is one modifier on paper and a different game in practice: two Act 3 bosses, fought in a row, with the second appearing on floor 49 immediately after the first. The wiki notes this is the only place in the game where a boss fight is not preceded by a rest site. You keep your remaining HP, your potions and your relics, and the ladder's final exam is whether one deck can answer two different mechanics checks back to back.
The design lineage explains the shape. A10 has been the experimental slot all through Early Access: Villainy in v0.76, Ascender's Scorn in v0.87, then Double Boss from v0.90 onward, a deliberate import of STS1's A20 finale. The community's verdict on the modern version is split and worth hearing both ways. One camp reports A10 feels like a reward rather than a spike, because the double gauntlet mostly tests whether your deck is honest, and by the time you have climbed nine levels it usually is. The other camp calls consecutive 400 to 600 HP bosses absurd, particularly when the pair is The Queen plus Aeonglass. Both camps agree on one tactical point, echoed across multiple threads: throttle your greed, because a deck built to win fight one by a landslide is often built to lose fight two by exactly that margin.
The organizing fact is that scaling resets between the two fights, as documented by guide sites (treat the detail as community-verified). Powers, Strength stacks and long setup do not transfer. Decks fall into three buckets against this rule. Slow engines that need three or four turns to come online pay their setup cost twice with no heal between fights, which is often fatal. One-shot burst decks that won fight one via a stacked combo start fight two from zero and may simply be too slow to rebuild. The decks that clear A10 are medium-speed consistent ones: block that does not depend on a long ramp, damage that re-establishes in a turn or two, and enough sustain to run two full boss fights.
Planning happens at the map. Both boss icons are visible from the start of the act, so you know your pair at floor 34, and the correct response is to budget the whole act around the weaker matchup: the Act 3 Ancient boon that patches it, the last shop purchase that answers it, and the card picks that cover it. Pantograph, healing 25 at the start of every boss combat, effectively pays out twice on this floor, which is why ladder climbers rate it so highly.
Last thing, and it is the level's one mercy: the reward for fight one is a full boss payout, gold and cards, so even a failed A10 attempt often ends the run richer than a won A9. If the gauntlet breaks you, bank the payout, drop back a level, and fix the hole the second boss exposed.
Coming from STS1: which of the old twenty levels survived
If you cleared levels in the first game, the fastest way to learn the STS2 ladder is a translation table, because the sequel compressed twenty levels into ten and edited the list on the way. The mappings below line up the official STS1 Ascension list with the STS2 wiki's level list, and knowing them spares you a week of stale instincts.
The survivors map almost one to one. STS1 A1 (more elites) is STS2 A1. STS1 A5, the post-boss heal cut to 75 percent, became STS2 A2 at 80 percent of missing HP, with one big scope change: it applies to every Ancient heal in the run, including Neow at the start, not just the heal after bosses. STS1 A13 (bosses give less gold) widened into STS2 A3, which cuts gold from all enemies and chests, not only bosses. STS1 A11 (one fewer potion slot) is STS2 A4 verbatim. STS1 A10's Ascender's Bane returns as STS2 A5 with a sequel twist, the Eternal keyword replacing the old cannot-be-removed wording, though the practical effect is the same. STS1 A16 (shops cost 10 percent more) narrowed into STS2 A6, which inflates only card removal and by a much steeper curve, 100 gold base plus 50 per removal. STS1 A12 (upgraded cards appear half as often) broadened into STS2 A7, which also halves rare cards. And STS1 A20's double boss is STS2 A10.
What did not survive matters just as much. STS2 has no equivalent of STS1 A6 (start each run damaged), A14 (lower starting Max HP), A15 (unfavorable events) or the A17 through A19 moveset upgrades for normal enemies, elites and bosses. The middle-of-the-ladder stat increases were also consolidated: STS1's three tougher-enemies tiers and three deadlier-enemies tiers became single steps at A8 and A9, tuned per enemy rather than by flat percentages.
Two consequences follow. First, STS2's ladder front-loads its economy pressure: three of the first six levels touch gold, healing or potions, which is why climbing feels like a resource squeeze long before enemies change. Second, because stat boosts land only at A8 and A9, the run-to-run difficulty between A1 and A7 is about discipline rather than math, and most losses in that range are drafting and routing errors, not stat walls.
The overall calibration, per repeated community reports, is that STS2 A10 sits below STS1 A20 in difficulty. Whether that holds for you depends on which character you climb with and how much of your STS1 skill was Heart-specific. The habits that transfer are the boring ones: thin decks, upgraded key cards, spent potions, planned elites.
Multiplayer Ascension: one ladder, one shared key
Co-op runs on a completely separate Ascension track, a split that has existed since the pre-Early-Access v0.50 builds and survives in v0.111. Nothing you unlock in multiplayer counts toward your single-player ladder and vice versa, so the two systems are parallel rather than connected, and the in-game UI even marks the multiplayer track with its own differently colored flame icon.
The rules have a cooperative flavor. A multiplayer win unlocks the next Ascension level for every character for every player in the lobby, regardless of who was actually played, which makes a four-player lobby a mutual unlocking machine: one carried friend at A5 pushes everyone toward A6. The counterweight is the cap. The lobby can only play as high as the lowest unlocked level among its members, so a veteran cannot drag a fresh account straight into A10 content; the group climbs at the pace of its least experienced player.
That asymmetry produces the track's actual strategy. If you are the experienced player, your job is building lobby-friendly decks: support and debuff effects that multiply the whole team's output, Mend at rest sites to heal allies for 30 percent of their max HP, thrown potions, and restraint about hogging card reward synergies. If you are the player being carried, the etiquette is the reverse: play the character the lobby is missing, avoid greedy archetypes that need three turns of setup while the team dies, and treat the runs as free lessons in how higher Ascension fights actually flow.
One planning note for mixed groups: enemy scaling in co-op is already steep by design, with multiplayer boss HP running at roughly 2.6 times single-player values in a two-player Act 3 boss fight, so stacking Ascension on top changes fight math significantly. Debuff-heavy and percentage-based strategies scale disproportionately well there, which is worth factoring into which levels your group attempts first.
The single most common multiplayer Ascension mistake is assuming the unlock is per character like single-player. It is not: one win moves the whole roster forward for everyone present. The second most common is grinding multiplayer levels expecting them to unlock single-player Ascensions. They never have. Keep the ladders mentally separate, use multiplayer as the fast, social way to open the track, and do your serious climbing alone.
A concrete climb plan: from first win to the double boss
Here is a level-by-level plan if you would rather not discover the ladder's lessons the expensive way. Start with the Ironclad, which every community difficulty thread rates the easiest climb, thanks to 80 starting HP, healing from the starter relic and Strength scaling that carries sloppy drafts. Do your first A1 through A3 runs with him, because those levels teach economy, not combat: A1 forces elite engagement, A2 teaches Max HP valuation, A3 teaches budgeting. Win each once, and resist the urge to speedrun levels; the unlocks are permanent and the habits compound.
At A4 and A5, rebuild your potion and deck hygiene before climbing further. Two potion slots means a rotation, not a vault: cast potions to save HP in normal fights and keep one slot for a planned boss answer. The Ascender's Bane means every draw-your-deck line needs to count one dead card per shuffle. If you have been skipping card removal because gold felt tight, A6 is about to make that habit unaffordable.
A6 through A7 are the economy exam. Budget thinning away from the merchant before the run starts: note which Ancient boons remove or transform, take event removals on sight, and let the shop sell you relics, which got cheaper in the same patch that repriced removal. Reorder your campfire logic toward Smith on A7, when the game stops handing out upgrades for free. These two levels will not kill you with stats; they will kill you with a deck that never came together, so audit drafts honestly.
Treat A8 as a rehearsal and A9 as the boss of the ladder. At A8, longer fights reward scaling, so if your deck's plan is front-load only, expect to gas out in Glory. At A9, redo the block math with the bestiary open: know the actual damage of the three moves each elite and boss uses, and stop estimating. Bank Max HP all run, spend potions on the telegraphed turns, and pick elites selectively. Most players need multiple attempts here, and that is normal; the level is widely considered the hardest jump in the game for a reason.
Then take A10 when the ladder offers it, and treat the pair on the map as the run's actual boss from floor 34. If the gauntlet breaks you, drop to A9, fix the exposed hole, and go again. Rotate characters on the second pass: the Silent and Necrobinder climbs teach resource math the Ironclad never demands, the Defect teaches engine timing, and community opinion is split on whether the Regent or the Necrobinder is the hardest, which tells you both reward practiced hands. Ten levels is a short ladder. Its top is reachable, and everything past it, alternate acts, the Watcher, and whatever the true ending at 1.0 adds, will be waiting with the same flame icon.