Undercards

Core Features That Make a Difference

Unique Soul Mechanic & Gameplay: Master the core Undertale souls—like Justice, Patience, Bravery, and Determination—each granting a unique, game-changing passive ability that defines your playstyle and strategy for the entire match.

Vast Collection of Fan-Favorite Cards: Build decks from hundreds of cards featuring meticulously pixel-art rendered characters, enemies, and items from across the Undertale world, each with abilities that reflect their in-game lore and personality.

Strategic Deck Building & Synergies: Craft decks around specific soul types or create hybrid strategies. Discover powerful synergies between cards, leveraging combo potential and board control tactics to outsmart your opponent.

Online PvP Ranked & Casual Modes: Test your decks against players worldwide in ranked matches to climb the ladder, or enjoy casual duels and special event modes that often introduce fun, rule-bending twists.

Single-Player Puzzles & Challenges: Engage your mind with challenging single-player puzzles that require precise card plays to solve, and tackle AI opponents to earn rewards and learn new strategies.

Who Is This App For?

Fans of Undertale who want to explore the world and characters through a new, strategic genre.

Collectible Card Game (CCG) enthusiasts looking for a game with a unique central mechanic (the Souls) and a strong thematic identity.

Players who enjoy tactical, turn-based gameplay that rewards careful planning, resource management, and understanding card synergies.

Anyone who appreciates pixel art, indie game passion projects, and supportive online gaming communities.

How to Use Undercards

Click “Check All Versions” below to download and install Undercards on your device or browser.

Complete the tutorial to understand the core mechanics: playing cards, spending Gold (mana), and the pivotal role of your chosen Soul at the start of each match.

Start by experimenting with the pre-built starter decks for each Soul type. Play against AI bots to get a feel for different playstyles without pressure.

Earn in-game currency (Dust) by playing games and completing quests. Use it to buy card packs and expand your collection.

Navigate to the deck builder. Select a Soul and add up to 30 cards, focusing on a clear strategy (e.g., aggro, control, combo). Pay attention to card costs and synergies.

Enter the "Play" menu to queue for an online match. Use your custom deck against real opponents, adapt your strategy on the fly, and aim to reduce your opponent's HP to zero to claim victory.

Dive back into the iconic underground world of monsters, but this time, your determination is measured in cards and strategy. Undercards is designed to be a loving tribute and a fresh strategic take on the beloved universe of Undertale, transforming its memorable characters, locations, and soul mechanics into a deep and engaging online collectible card game (CCG). Whether you're a fan of the original RPG drawn to see Toriel, Sans, and Flowey in a new light, or a competitive card game player looking for a unique tactical challenge, this game offers a rich blend of nostalgia and original gameplay. It’s more than just a fan game; it’s a fully-fledged strategic battleground, thoughtfully crafted with soul-based mechanics, deck-building depth, and a vibrant community that celebrates the "heart" of its source material.

Core Features That Make a Difference

Unique Soul Mechanic & Gameplay: Master the core Undertale souls—like Justice, Patience, Bravery, and Determination—each granting a unique, game-changing passive ability that defines your playstyle and strategy for the entire match.
Vast Collection of Fan-Favorite Cards: Build decks from hundreds of cards featuring meticulously pixel-art rendered characters, enemies, and items from across the Undertale world, each with abilities that reflect their in-game lore and personality.
Strategic Deck Building & Synergies: Craft decks around specific soul types or create hybrid strategies. Discover powerful synergies between cards, leveraging combo potential and board control tactics to outsmart your opponent.
Online PvP Ranked & Casual Modes: Test your decks against players worldwide in ranked matches to climb the ladder, or enjoy casual duels and special event modes that often introduce fun, rule-bending twists.
Single-Player Puzzles & Challenges: Engage your mind with challenging single-player puzzles that require precise card plays to solve, and tackle AI opponents to earn rewards and learn new strategies.

Who Is This App For?

Fans of Undertale who want to explore the world and characters through a new, strategic genre.
Collectible Card Game (CCG) enthusiasts looking for a game with a unique central mechanic (the Souls) and a strong thematic identity.
Players who enjoy tactical, turn-based gameplay that rewards careful planning, resource management, and understanding card synergies.
Anyone who appreciates pixel art, indie game passion projects, and supportive online gaming communities.

How to Use Undercards

Click “Check All Versions” below to download and install Undercards on your device or browser.
Complete the tutorial to understand the core mechanics: playing cards, spending Gold (mana), and the pivotal role of your chosen Soul at the start of each match.
Start by experimenting with the pre-built starter decks for each Soul type. Play against AI bots to get a feel for different playstyles without pressure.
Earn in-game currency (Dust) by playing games and completing quests. Use it to buy card packs and expand your collection.
Navigate to the deck builder. Select a Soul and add up to 30 cards, focusing on a clear strategy (e.g., aggro, control, combo). Pay attention to card costs and synergies.
Enter the "Play" menu to queue for an online match. Use your custom deck against real opponents, adapt your strategy on the fly, and aim to reduce your opponent's HP to zero to claim victory.