Safe setup turns
Slow Powers can win the long fight, but only when the deck can survive the turn spent putting them into play. A scaling engine that requires you to take a full attack undefended is not yet a reliable Aeonglass plan.
Slay the Spire 2 Boss
Aeonglass Boss Guide
Base HP
512
Ascension HP
535
Moves
3
Encounters
1
Version Intelligence
Main vs Beta
This entry uses the Main database by default. The current Beta changes the values shown below.
Main
v0.107.1
Beta
v0.111.0
Ebb Damage
Main
26(32)
Beta
22(26)
Changed in
v0.109.0
Boss Strategy
How to Beat Aeonglass
Quick Strategy
Treat Aeonglass as a consistency check, not only a scaling check. Its repeating Ebb → Eye Lasers → Increasing Intensity cycle gives you time to build power, but only if your setup turns remain defensible. Strip its starting Artifact before relying on Weak or Vulnerable, keep enough card access or Status cleanup to preserve important draws, and use your scaling to end the fight rather than spending every safe turn adding more setup.
What This Fight Tests
Artifact handling
Aeonglass starts with 3 Artifact. Decks that depend on Weak, Vulnerable, or another important debuff need enough separate applications to remove those layers before the real debuff plan begins working.
Draw consistency
The repeating fight becomes much harder when important Block, scaling, or payoff cards arrive in the wrong order. Card access matters because the deck has to execute through both damage turns and growing Status pressure.
Long-fight conversion
Scaling is useful here, but eventually it has to become damage. Once the engine is online, continuing to add setup instead of converting that advantage into a kill can create unnecessary extra cycles.
Key Decisions
Enough scaling is not the same as enough setup time
A deck can have an excellent late-fight engine and still be vulnerable if its most important Power costs an entire turn of Energy or arrives beside no defense. Before the fight, I care about whether the engine can be established safely, not just how strong it becomes afterward.
Strip Artifact before judging your debuffs
Weak and Vulnerable can look ineffective here when the real problem is simply that Artifact is absorbing the first applications. If those debuffs are central to the deck, plan enough independent applications to clear Artifact first.
A defensive potion should have a job
If the deck has one predictable setup turn where Block can collapse, I would rather reserve a defensive potion for that window than save it without a specific purpose. Potions are most valuable when they turn a known losing draw into a survivable one.
Stop adding engine once the engine already wins
After damage scaling, draw, and defense are functioning, another setup piece can be worse than a card that immediately converts the engine into damage or protects its weakest turn. Aeonglass rewards a complete plan more than an oversized one.
Combat State
Innate Powers
Combat Data
Moves
3
moves
Ebb
Attack Defend
EBB
Damage
26 → 32
Block
33
Eye Lasers
Attack
EYE_LASERS
Damage
11 × 2 → 12 × 2
22 → 24 total
Increasing Intensity
Status Buff
INCREASING_INTENSITY
Enemy AI
Attack Pattern
CycleEbb → Eye Lasers → Increasing Intensity → repeat
Initial move:
Ebb
View pattern states
Ebb
move
Next:
EYE_LASERS_MOVE
Eye Lasers
move
Next:
INCREASING_INTENSITY_MOVE
Increasing Intensity
move
Next:
EBB_MOVE
Fight Plan
Aeonglass Fight Plan
The raw move pattern tells you what is coming. This plan focuses on what I want the deck to accomplish before each dangerous part of the fight.
Phase 01
Opening cycle
Establish only the setup you can afford while preserving enough defense for the first Ebb and the attack that follows.
- Account for Ebb immediately. It attacks while also giving Aeonglass Block, so a weak opening hand can lose both HP and early damage tempo at the same time.
- If an expensive Power is your main scaling plan, check the rest of the hand before automatically playing it. The important question is whether that setup turn leaves a survivable next draw.
- If Weak or Vulnerable is central to the deck, begin clearing the 3 starting Artifact instead of assuming the first debuff application will solve the matchup.
Watch for
- Using the entire turn on setup with no defensive fallback.
- Treating a bad opening draw as harmless because the deck scales well later.
Phase 02
First full cycle
Stabilize the engine through Eye Lasers and Increasing Intensity without allowing card access to collapse.
- Keep a dense defensive answer available for the attack portions of the cycle rather than spending every good hand on additional setup.
- Once Artifact has been removed, use important Weak or Vulnerable applications where they actually change survival or damage instead of spending them only to strip layers.
- Protect access to the cards that make the deck function. Status pressure matters most when it delays the Block, draw, Energy, or payoff card you needed on that exact turn.
Watch for
- Drawing the engine without enough Energy to both establish it and survive.
- A hand becoming larger or less reliable while the important cards remain difficult to reach.
Phase 03
Conversion
Turn established scaling into a kill before another cycle creates a new consistency problem.
- Once scaling is online, prioritize the attacks or payoffs that convert it into real damage.
- Do not spend a safe turn adding another redundant engine piece when the deck already has enough long-fight power.
- Keep enough defense for one imperfect draw. A winning engine still loses if the deck reaches one attack turn with no playable defensive line.
Watch for
- Over-scaling instead of ending the fight.
- Assuming the next draw will contain Block because previous turns were comfortable.
Dangerous Turns & Windows
Danger Window
Opening Ebb
Ebb combines meaningful damage with 33 Block. On Ascension the hit rises from 26 to 32, so spending the opening entirely on slow setup can put the run behind before the engine is established.
Response:
Use the first cycle to balance setup with survival. If the engine needs a costly Power, Energy support or a defensive fallback makes that setup much safer.
Danger Window
Eye Lasers
Eye Lasers is a two-hit attack: 11 × 2 normally and 12 × 2 on Ascension. A deck that only blocks efficiently on ideal hands can still leak a large amount of HP here.
Response:
Have a reliable defensive line rather than counting on one specific Block draw. Multi-hit mitigation becomes especially useful when it fits the character naturally.
Danger Window
After Increasing Intensity
Increasing Intensity introduces Status and buff pressure before the cycle returns to Ebb. The longer the fight continues, the more important it becomes that your important cards remain accessible.
Response:
Use card access and Status-control tools to protect the deck’s functional turns, then convert established scaling into damage instead of deliberately extending the fight.
Before the Fight
How to Prepare for Aeonglass
I use these checks before committing the final rewards, upgrades, shop purchases, and potions leading into the Boss.
DefenseCritical
Can I survive while setting up my engine?
Ready when
The deck can play its important scaling Power or engine piece without automatically giving up the entire defensive turn, or it has a potion or Energy line that covers that weakness.
Warning
A deck that wins only after several Powers are active can still lose before those Powers are safely established.
Card accessHigh
Can I find Block and scaling in the right order?
Ready when
Draw, deck thinning, Exhaust, or other access tools make it reasonably likely that the deck reaches the card it needs rather than relying on one perfect draw order.
Warning
Strong cards do not solve the fight when they arrive one turn after they were needed.
DebuffsHigh
Does my plan depend on Weak or Vulnerable?
Ready when
The deck has enough separate debuff applications to work through Aeonglass’s 3 Artifact before relying on the important effect.
Warning
One premium debuff card can still accomplish almost nothing if all of its useful effects are absorbed by Artifact.
Status controlHigh
What happens when Status cards enter the deck?
Ready when
The deck has enough access or cleanup that Status pressure does not repeatedly delay its core defensive and scaling turns.
Warning
The problem is not simply having unwanted cards. The dangerous part is drawing them instead of the answer required for the current attack.
EnergyMedium
Can I afford my expensive setup cards?
Ready when
Important Powers can be played without shutting down the rest of the turn, or an Energy source or potion can bridge the vulnerable setup window.
Warning
Expensive scaling becomes much less reliable when playing it leaves no Energy for defense or card access.
PotionMedium
Which bad turn is my potion supposed to fix?
Ready when
At least one potion has a clear matchup role: protect a dangerous setup turn, reinforce scaling, or rescue a bad draw.
Warning
Saving every potion has no value if the run dies during the exact window the potion could have covered.
Character Matchups
Aeonglass by Character
The Boss does not change between characters, but the part of the fight that matters most often does. These notes focus on what each character should adjust rather than repeating the general strategy.
Ironclad can scale hard enough to beat Aeonglass, but slow Power-heavy versions need to solve the setup turn first. Exhaust is particularly valuable because it can protect card access while converting unwanted non-Attack cards into Block or draw. If the deck relies on Weak or Vulnerable, cards that apply multiple debuffs also gain value because Aeonglass begins behind several Artifact layers.
Prioritize
- Use controlled Exhaust to keep Status pressure from choking important draws.
- Value Artifact stripping when Weak or Vulnerable is part of the defensive or damage plan.
- Make sure expensive scaling such as Demon Form has enough Energy and defense around the setup turn.
- Once Strength is online, prioritize a real damage payoff rather than continuing to collect scaling.
Watch for
- Playing an expensive Power simply because the matchup is long enough for it to scale.
- Reaching an attack turn after setup with no actual Block line available.
Silent should separate Artifact removal from the debuff that actually matters. Efficient stripping is valuable when the deck wants Weak or Vulnerable to stick, especially in physical-damage builds. The goal is not to add debuffs blindly; it is to clear the protection cheaply enough that the important application works when the dangerous turn arrives.
Prioritize
- Strip Artifact efficiently before depending on Weak or Vulnerable.
- Preserve enough card access that defensive tools arrive on the attack turns rather than disappearing behind low-impact draws.
- Use physical-damage amplification only after the Artifact problem has actually been solved.
Watch for
- Counting a debuff as defensive coverage before checking whether Artifact will absorb it.
- Adding more synergy when the real problem is surviving one bad attack turn.
Defect benefits from deciding what the Aeonglass fight needs before the final shop rather than waiting for the fight to expose the weakness. If Orb scaling is already the win condition, targeted Focus support can be more valuable than another generic reward. Matchup-specific purchases can also cover Aeonglass without forcing the whole deck into a different build.
Prioritize
- Check whether the existing Orb plan already has enough scaling and instead needs consistency or a one-fight power boost.
- Treat Focus support as a matchup tool when it meaningfully improves an already functional Orb engine.
- Consider matchup-specific shop options instead of adding another generic card that does not solve the Aeonglass problem.
Watch for
- Adding more engine pieces when the deck already scales but cannot execute safely.
- Entering the fight without a plan for the deck’s weakest setup or defensive turn.
Failure Analysis
Common Aeonglass Mistakes
These are the decisions that can make a deck look strong on paper but still fail this specific fight.
01
Treating a slow scaling card as an automatic Boss solution
You see a long Boss fight and assume an expensive scaling Power is automatically correct.
Why it fails
The Power may eventually win, but the deck still has to survive the turn spent playing it and the draws immediately afterward. Aeonglass can punish the gap between establishing scaling and actually becoming safe.
Better decision
Judge the entire setup sequence. If the Power consumes most of the turn, make sure Energy, Block, or a potion covers the window before committing to it.
02
Saving a defensive potion without assigning it a turn
You preserve the potion because the deck looks strong overall, even though one setup or bad-draw turn is clearly the matchup’s weak point.
Why it fails
The run can die with resources still unused. A potion has no future value after the one vulnerable turn ends the fight.
Better decision
Before combat, decide which draw or setup window the potion is allowed to rescue. Use it when that condition actually occurs.
03
Applying the important debuff into Artifact
You count Weak or Vulnerable as part of your plan without first budgeting enough applications to remove Aeonglass’s starting Artifact.
Why it fails
Artifact absorbs those applications before the effect that your defense or damage plan depends on can stick.
Better decision
Use cheaper or multi-effect applications to strip Artifact first, then land the debuff on the turn where it changes the fight.
04
Ignoring draw-order failure
The deck contains enough Block, scaling, and damage in total, so you assume the matchup is solved.
Why it fails
Aeonglass tests whether those cards appear in usable combinations. One attack turn with the wrong half of the deck can undo an otherwise winning engine.
Better decision
Improve card access or preserve a fallback line for bad draws instead of evaluating the deck only by its best possible hand.
05
Continuing to scale after the deck is already online
You spend additional safe turns adding redundant Powers or engine pieces instead of converting existing scaling into damage.
Why it fails
Every additional cycle exposes the deck to more attack turns and more Status pressure without necessarily improving the chance to win.
Better decision
Once defense and scaling are established, shift reward and turn priority toward reliable damage conversion and ending the fight.
Entity Relationships
Appears In
1
encounter
Aeonglass
Boss
Game ID:
AEONGLASS
Data version:
v0.107.1 · Main
Type:
Boss