Louse Progenitor

Monster
Health
135/140 HPAny number from 134 to 136, rolled when the fight starts. From 138 to 141 from Ascension 8.
Gold
1511 goldAny amount from 10 to 20, rolled when the fight ends. 7 to 15 from Ascension 3.Any amount from 7 to 15, rolled when the fight ends. 10 to 20 below Ascension 3.
Found in
HiveMonster room, alone, 1 in 10 from the normal pool.
Starts with
14 Curl Up
attack/attack9/10debuffFrail2Frail
Louse Progenitor135/135/140/140Louse ProgenitorCurl Up14

Turn 1

How to beat Louse Progenitor

The Strength race

  • Everything scales off Curl and Grow: it gains 5 Strength every three turns and you cannot stop it, so this is a race.

The damage window

  • Your best damage window is the turn after Web Cannon, when it has no Block unless Curl Up has already fired.
  • Lead with your biggest Attack, because Curl Up's Block arrives only after the card that triggered it resolves. A multi-hit card gets all of its hits in first.

Reading its Block

  • The turn after Curl and Grow it sits behind 14 (18) Block, so use that turn for setup.
  • Frail from Web Cannon covers the Pounce turn, so plan for 25 percent less Block right when the biggest hit comes.

Notes

  • Normal Hive encounter, always alone.
  • HP 134 to 136 (138 to 141 at Ascension 8+).
  • Curl Up only responds to attack damage that scales with powers and comes from a card, so poison or relic damage will not trigger it.
  • The curled pose seen in Web Cannon and Pounce is animation only.

Changes by version

  1. 13 Aug 2026Upgraded Strength gain at A957Playtest
    Strength gain at A9 with Ascension increased from 5 to 7
  2. 29 Jan 2026NumberInternal playtest
    HP changed from 134(136)-139(141) to 134(138)-136(141) and Curl Up move's Block gain now scales with Ascension increased from 14 to 18
  3. 15 Jan 2026ChangeWeakFrailInternal playtest
    Web move changed from applying Weak to Frail
All 5 patch notes2 older
  1. 8 Jan 2026InterfaceInternal playtest
    Raised intent slightly for Louse Progenitor as when it's curled up it's taller
  2. 18 Dec 2025ChangeInternal playtest
    Slight rework of moveset and values

Internal playtest notes are from before the Early Access release. Names and numbers in them can differ from the game today.

Purchase today
If you haven't bought Slay The Spire 2 yet, it's time. Support the devs, they made an amazing game.Get it on Steam