Slay the Spire 2 · Act 1
Act 1 bosses — Overgrowth & Underdocks
Act 1 is short, but the boss you draw is decided by which biome the run rolls. You will face one boss from the active biome's pool of three, so route and draft with both possibilities in mind.
Act 1 in Slay the Spire 2 uses alternate biomes. Each run lands in either the Overgrowth or the Underdocks, and you fight one boss from that biome. The act is the runway — you cannot draft a perfect answer to every boss this early, so the goal is a deck with enough damage density and a real burst turn, plus at least one tool that does not care about your stats (poison, orbs, AoE).
Because you do not get to pick the biome, prioritise flexible power over a hard counter: Weak to tame multi-hit attacks, a way to bypass block or Strength scaling, and enough block to survive a telegraphed big swing. Knowing each boss's one defining trick is more useful than memorising numbers, which shift between Early Access patches.
Act 1
Overgrowth bosses
The forested biome. These fights reward scaling setup during dormant turns and consistent Weak/Vulnerable once the boss commits.
How to beat Ceremonial Beast
A dormant brute that spends its opening turns powering up — stacking Strength and a Ritual-style per-turn buff — before waking into escalating multi-hit attacks. The longer the fight runs, the harder every hit lands, so it is fundamentally a race against its own scaling.
How to beat The Kin
A multi-enemy fight: a back-line Kin Priest that piles on Frail and Weak while front-line followers deal the bulk of the melee damage and buff their own Strength. It is a target-priority puzzle, not a damage check.
How to beat Vantom
An ink-themed predator that alternates between an aggressive stance (heavy single hits plus Frail to choke your block) and a defensive stance where it stacks block and charges a large delayed swing. Reading which stance it is in dictates whether you defend or commit.
Act 1
Underdocks bosses
The flooded biome. Expect stat drains, status-card pressure, and a detonation gimmick — block-ignoring damage and hand-cycling shine.
How to beat Lagavulin Matriarch
Starts asleep behind heavy armor and, once awake, repeatedly debuffs your Strength and Dexterity while buffing her own. Every drain cycle permanently weakens your attacks and block, so the fight only gets worse the longer it lasts.
How to beat Soul Fysh
A pattern fight: Soul Fysh dumps Beckon status cards into your deck (1 energy; if not exhausted or discarded by end of turn they hit you for unblockable damage) and periodically turns Intangible, reducing your hits to 1. Winning means cycling Beckons out and saving burst for the windows it is vulnerable.
How to beat Waterfall Giant
A large solo body whose signature trick is that it does not die at 0 HP — instead it detonates on its next turn, so the lethal blow is followed by a big explosive blast you have to survive.