Ascension in Slay the Spire 2 is not a vague difficulty slider. The monster file carries an explicit Ascension value beside almost every number, and the pattern is consistent: 102 of the 104 monsters with both values gain HP (average +5.60, range +1 to +23) and 196 of the 224 damaging moves hit harder.
The data stores one Ascension value per monster rather than a per-level table, so this page works at the fight level: what goes up, by how much, and which fights change shape rather than just length.
The HP column
| Measure | Value |
|---|---|
| Monsters with a normal and Ascension HP value | 104 |
| Monsters that gain HP | 102 |
| Monsters unchanged | 2 |
| Smallest increase | +1 |
| Largest increase | +23 |
| Average increase | +5.60 |
The two that do not move are The Adversary Mk 2 (200 HP) and Mk 3 (300 HP) — both fixed bodies. Osty and the three 9,999 HP scripted entries carry no Ascension value at all, so they neither rise nor stay: there is simply nothing to compare.
The biggest HP jumps
| Monster | Normal | Ascension | Change | Percent |
|---|---|---|---|---|
| Aeonglass | 512 | 535 | +23 | 4.5% |
| Knowledge Demon | 379 | 399 | +20 | 5.3% |
| The Insatiable | 321 | 341 | +20 | 6.2% |
| Mecha Knight | 300 | 320 | +20 | 6.7% |
| Slimed Berserker | 261 | 281 | +20 | 7.7% |
| Queen | 400 | 419 | +19 | 4.8% |
| Soul Nexus | 234 | 254 | +20 | 8.5% |
| Owl Magistrate | 231 | 247 | +16 | 6.9% |
The percentages are the part that matters. Aeonglass takes the largest raw jump and the second smallest percentage — +23 on a 512 pool is 4.5%. Soul Nexus takes the same +20 as Knowledge Demon but on a 234 pool, which is 8.5%.
If you plan around raw HP, the Act 3 bosses look like the big losers. If you plan around percentage, the mid-HP elites are where Ascension bites hardest.
The smallest HP jumps
| Monster | Normal | Ascension | Change |
|---|---|---|---|
| Assassin Raider | 18 | 19 | +1 |
| Axe Raider | 20 | 21 | +1 |
| Bowlbug (Nectar) | 35 | 36 | +1 |
| Bowlbug (Egg) | 21 | 23 | +2 |
| Kin Follower | 58 | 62 | +4 |
| Vantom | 173 | 183 | +10 |
| Ceremonial Beast | 252 | 262 | +10 |
A +1 on an 18 HP raider is 5.6%, which is proportionally the same as Aeonglass’s 4.5%. The flat step is small because the pool is small, not because the fight is easy.
Damage scales with the HP
196 of the 224 damaging moves carry a higher Ascension value. The six biggest deltas:
| Move | Monster | Normal | Ascension | Change |
|---|---|---|---|---|
| Ebb | Aeonglass | 26 | 32 | +6 |
| Beetle Charge | Frog Knight | 35 | 40 | +5 |
| Magic Bomb | Magi Knight | 35 | 40 | +5 |
| Heavy Cleave | Mecha Knight | 35 | 40 | +5 |
| Charge | Mecha Knight | 25 | 30 | +5 |
| Laser | Rocket | 31 | 35 | +4 |
And the ones that decide Act 3:
| Move | Monster | Normal | Ascension | Change |
|---|---|---|---|---|
| Lunging Bite | The Insatiable | 28 | 31 | +3 |
| Dismember | Vantom | 26 | 30 | +4 |
| Ponder | Knowledge Demon | 11 | 13 | +2 |
| Execution | Queen | 15 | 18 | +3 |
| Knowledge Overwhelming | Knowledge Demon | 8×3 = 24 | 9×3 = 27 | +3 |
| Off with Your Head | Queen | 3×5 = 15 | 4×5 = 20 | +5 |
Vantom’s Dismember going 26 → 30 is a 15.4% increase. A block plan built for 26 fails at 30, and unlike Aeonglass’s Ebb there is no 33 Block on her side to give you a slow turn.
Innate powers move too
Nine of the 51 innate powers have a higher Ascension value. These are the quiet changes that alter a fight before the first card is played.
| Monster | Power | Normal | Ascension |
|---|---|---|---|
| Terror Eel | Shriek | 70 | 75 |
| Phantasmal Gardener | Skittish | 6 | 7 |
| Slumbering Beetle | Plating | 15 | 18 |
| Frog Knight | Plating | 15 | 19 |
| Louse Progenitor | Curl Up | 14 | 18 |
| Corpse Slug | Ravenous | 4 | 5 |
| Infested Prism | Vital Spark | 2 | 3 |
| Test Subject #C14 | Enrage | 2 | 3 |
| Vantom | Slippery | 8 | 9 |
Frog Knight’s Plating going 15 → 19 is the largest of the nine (+26.7%), and it lands on an elite with 191 HP. Vantom’s Slippery going 8 → 9 is smaller in raw terms but applies to a boss you meet in Act 1.
“Ebb — Attack + Defend, 26 damage (32 at Ascension), gains 33 Block.” — STS2 monster data, slaythespire.wiki.gg
What actually changes in a fight
Three effects, in order of how much they cost you:
- Longer fights. +5.60 average HP is roughly one extra turn of damage across a normal encounter. On a 20-card deck drawing five a turn, one extra turn is one extra hand.
- Higher spikes. The damage deltas are concentrated on the biggest moves, so the turn that already required your best block now requires more.
- Bigger defensive powers. Plating and Curl Up rising means the first turns are slower, which pushes the fight toward the turns where the boss has scaled.
The interaction matters most on bosses with fixed cycles. Aeonglass’s Ebb at 32 needs 32 Block on a known turn; you can plan for it. The Insatiable’s Lunging Bite at 31 arrives on turn 3 of a five-move loop, so it is equally predictable — the problem is that both numbers now exceed what a single 30-Block card covers.
Where to go next
The boss table sorts every fight by HP and biggest hit, and the monster index holds the full Ascension column for all 115 entries. If you are building for the higher damage numbers, the cards database lists every block card with its value, and deckbuilding basics covers how much defence a deck needs. The relics database is where the passive Block and Strength sources live.