STS Arena

If you find yourself asking "Does this deck beat Gremlin Nob?", why not just check? Practice fights in Slay the Spire to improve your tactical play and get a better sense of the strength of different decks.

Installation

Requirements

Installation Steps

  1. Subscribe to ModTheSpire and BaseMod on the Steam Workshop
  2. Download STSArena-0.4.0.jar (or see all releases)
  3. Place STSArena.jar in your Slay the Spire mods folder:
    • Windows: C:\Program Files (x86)\Steam\steamapps\common\SlayTheSpire\mods\
    • macOS: ~/Library/Application Support/Steam/steamapps/common/SlayTheSpire/SlayTheSpire.app/Contents/Resources/mods/
    • Linux: ~/.local/share/Steam/steamapps/common/SlayTheSpire/mods/
  4. Launch the game through ModTheSpire and enable "STS Arena" in the mod list

Quick Start

Get started with arena practice in just a few clicks:

  1. From the main menu, click Arena Mode
  2. Select a saved loadout or choose New Random Loadout
  3. Pick an encounter (enemy) to fight
  4. Battle! After winning or losing, you can:
    • Rematch - Try the same fight again
    • Modify Deck - Tweak your loadout and retry
    • Continue - Return to selection screens
Main menu with Arena Mode button

The Arena Mode button appears on the main menu

Features

Custom Loadouts

Build any deck with any cards, relics, and potions. Perfect for testing specific strategies or learning card interactions.

Any Encounter

Fight any enemy in the game - from early Cultists to The Heart. Practice bosses, elites, or tricky enemy combinations.

Instant Retry

Lost a fight? Retry immediately with the same or modified loadout. No need to start a new run.

Practice from Run

Mid-run against a tough fight? Use "Practice in Arena" from the pause menu to practice with your current deck.

Statistics Tracking

Track your win rate against specific encounters. See which fights give you trouble and measure improvement.

Save Management

Arena fights don't affect your normal run saves. Practice freely without worry.

Loadout Management

Loadout Selection Screen

The loadout selection screen shows all your saved loadouts. Hover over a loadout to preview its contents.

Loadout selection screen

Select from saved loadouts or create a new random one

Available Actions

Creating Custom Loadouts

Use the Loadout Creator to build custom decks from scratch:

Loadout creator screen

Build custom loadouts with any cards, relics, and potions

Creator Features:

Encounter Selection

After selecting a loadout, choose which enemy to fight:

Encounter selection screen

Choose any encounter from any act

Encounter Categories

Category Examples
Act 1 Normal Cultist, Jaw Worm, 2 Lice, Gremlin Gang
Act 1 Elite Gremlin Nob, Lagavulin, 3 Sentries
Act 1 Boss The Guardian, Hexaghost, Slime Boss
Act 2 Normal Chosen, Byrd, Snecko, Cultist and Chosen
Act 2 Elite Gremlin Leader, Book of Stabbing, Slavers
Act 2 Boss The Champ, Collector, Automaton
Act 3 Normal Darklings, Orb Walker, Jaw Worm Horde
Act 3 Elite Giant Head, Nemesis, Reptomancer
Act 3 Boss Awakened One, Time Eater, Donu and Deca
Act 4 Shield and Spear, The Heart

Tip: Use the search box to quickly find specific encounters. The list shows your win/loss record for each encounter with the current loadout.

Arena Combat

Arena combat works just like normal Slay the Spire combat:

Arena combat

Combat plays exactly like the base game

Key Differences from Normal Runs

Victory Screen

After winning, you can choose to:

Arena victory screen

Victory options: Continue, Retry, or Edit Loadout

Defeat Screen

After losing, you can immediately retry:

Arena defeat screen

Defeat options: Continue, Retry, or Edit Loadout

Practice from Normal Run

Facing a tough fight in your normal run? Use the pause menu to practice:

Pause menu with Practice in Arena

The "Practice in Arena" button appears in the pause menu during normal runs

How It Works

  1. During a normal run, press Escape to open the pause menu
  2. Click Practice in Arena
  3. Your current deck, relics, and potions are saved as a new loadout
  4. Select an encounter to practice against
  5. After practicing, you can return to your normal run

Note: Your normal run save is completely protected. Arena practice doesn't affect your run in any way.

Practice from Death Screen

If you die during a normal run, you can also practice from the death screen:

Death screen with Practice in Arena button

The death screen includes a "Practice in Arena" button to analyze what went wrong

This is especially useful for analyzing tough fights - you can immediately retry the encounter that ended your run with the exact deck you had.

History & Statistics

Fight History

View your recent arena fights with detailed information:

Fight history screen

Fight history shows loadout, encounter, outcome, and date

Statistics Screen

Track your performance across loadout+encounter combinations:

Statistics screen

Statistics show win rates for each loadout vs encounter

Tracked Metrics