Learn the exact unlock requirement, discover every modifier, and find hidden challenge seeds that reshape your runs.
Custom Mode in Slay the Spire 2 tears up the rulebook and hands you the pieces to reassemble. The catch is that the game doesn’t hand it over right away — you need to prove yourself in the standard climb first.
In this guide we’ll cover the exact unlock requirement, what Custom Mode lets you control, every available modifier, and the hidden challenge seeds waiting to reshape your runs.
How to unlock Custom Mode
You must complete Glory (Act 3) three times.
Each victory advances the Timeline meta-progression in the Magnum Opus section. On your third successful run, you automatically discover the Seeds Epoch — chapter 4 of Magnum Opus. This discovery permanently unlocks Custom Mode for all future play.
What Custom Mode does and its restrictions
Custom Mode lets you enable any number of optional modifiers that alter deck building and combat. You can also set a specific run seed, manually pick your Ascension level, and swap in cards from other character pools.
The mode comes with trade-offs. Achievements and Leaderboards are disabled while playing Custom Mode, and completing a custom run does not raise your Ascension level with the character. Some modifiers also remove Neow’s standard starting bonuses.
All available custom modifiers
The following modifiers can be activated to create unique challenges or power fantasies.
Deck building modifiers
- Draft: Choose 10 card rewards to replace your starting deck. This disables Neow’s bonuses and prevents Pandora’s Box from appearing.
- Sealed Deck: Pick 10 cards from a pool of 30 to form your starting deck.
- Hoarder: Each time you add a card to your deck, you receive 2 extra copies. You can no longer remove cards at The Merchant.
- Specialized: Start with 5 copies of a single random card.
- Insanity: Start with a random deck of 30 cards.
- All Star: Start with 5 Colorless cards.
Gameplay and combat modifiers
- Flight: Ignore paths when choosing the next room, functioning like infinite Wing Boots charges.
- Vintage: Normal enemies drop Relics instead of cards.
- Deadly Events: Unknown rooms can now contain Elites but are also more likely to hold Treasure rooms.
- Midas: Enemies drop 200% more Gold, but you can no longer Smith at Rest Sites.
- Murderous: Both the player and all enemies start each combat with 3 Strength.
- Night Terrors: Resting at Rest Sites heals 100% of your HP but reduces your Max HP by 5.
- Terminal: Each time you enter a new room, you lose 1 Max HP. You start each combat with 5 Plating to compensate.
- Cursed Run: At the start of each Act, a random Curse (Clumsy, Debt, Decay, or Regret) is added to your deck.
Character cross-pollination
You can enable specific modifiers to make Ironclad, Silent, Regent, Necrobinder, or Defect cards appear in rewards and shops during the run.
Special challenge seeds
Enter these specific seeds in the text box above the Ascension selector to activate preset challenge runs.
- STARTERDECK: Grants Busted Crown and Binary — enemies drop 0 cards.
- MEGADRAFT: Activates Diverse and Draft, letting you draft from every character’s card pool.
- FADEAWAY: Activates Night Terrors and Terminal, creating a race against your constantly depleting Max HP.
- Y0URET00SL0W: Applies the Time Dilation modifier, giving all enemies the Slow debuff.
- 1HITWONDER: You start the game with only 1 Max HP.
Custom Mode shreds the standard climb and lets you test every wild deck idea you have, but pushing Ascension still belongs to the normal game mode. The full Ironclad and Silent guides for Slay the Spire 2 live on Solo Jugadores for when you’re ready to climb without safety nets.
