Game Design Document — Prototype Brief
Legends of the Diaspora
Contents
Crossroads is a web-based, 1v1 digital strategy card game set in a mythologized world rooted in African, Caribbean, and Afro-diaspora culture — where Orisha gods, Maroon warriors, Arawak spirits, and Caribbean outlaws battle for control of the eternal crossing point between worlds.
The game is heavily inspired by Legends of Runeterra (Riot Games) in terms of card game mechanics — but its world, characters, mythology, and aesthetic are drawn entirely from West African empires, Caribbean folklore, indigenous Arawak/Taíno tradition, and Afro-Caribbean spiritual practice.
The "Crossroads" is the central myth of the game world — a liminal place where all realities, islands, and spirit planes converge. Every faction is fighting to control or destroy it. Papa Legba guards the gate. The player chooses a side.
Most card games draw from European fantasy, East Asian mythology, or generic sci-fi. Crossroads occupies a completely unclaimed cultural space — giving players (especially in the Caribbean and African diaspora) characters and stories they've never seen as the heroes of a strategy game.
Commercially, this positions the game uniquely for Caribbean and diaspora audiences in the US, UK, Canada, and Africa — markets that are underserved and culturally hungry for authentic representation.
Two players face each other. Each controls a Nexus — their home territory. The goal is to reduce the opponent's Nexus from 20 health to 0 by summoning units, casting spells, and deploying powerful Champion cards.
The game is alternating and reactive — unlike Hearthstone where one player takes a full turn, Crossroads uses a pass-and-respond system. When one player plays a card, the other can respond before it resolves. This means both players are always mentally engaged.
Each round, one player is the Attacker and the other is the Defender. The attacker declares which of their units are attacking. The defender then chooses how to block, which units to sacrifice, or which spells to cast in response. This creates constant tactical decisions for both players.
Crossroads adds a unique mechanic not in Runeterra — a Spirit Gauge. Certain actions (playing cards with the Offering keyword, units dying in battle, spells from the Orisha Court faction) fill a shared Spirit Gauge. When it reaches 10, special Manifestation events trigger — powerful environmental effects tied to the current season (Harvest, Carnival, Hurricane, Dry Season) that affect both players. This adds a rhythm and urgency to matches that feels rooted in natural cycles.
Both players gain +1 Mana Crystal (max 10). Both draw one card. The Spirit Gauge fills by 1 if any unit died last round.
The active player (determined by who holds the Attack Token) may play cards, summon units, or cast spells. The opponent may respond with spell cards after each action. Either player can pass priority.
If the active player chooses to attack, they declare attackers. Defender assigns blockers. Combat is resolved simultaneously — both attacker and defender take damage equal to the opposing unit's Power. Units with 0 Health or less are destroyed.
Post-combat effects resolve. Units with Ancestor keyword return effects trigger. The Attack Token passes to the other player. If the Spirit Gauge reached 10, a Manifestation event triggers before passing.
Unused mana does not carry over — but 1 mana crystal converts to a Spirit Coin that can be used for faction-specific passive abilities next round.
There are three ways to win in Crossroads:
Reduce the opponent's Nexus from 20 to 0 HP through direct combat or spell damage. The standard win condition.
Trigger 3 Manifestation events in a single game using the Spirit Gauge (a specialty path for Orisha Court and Maroon Highlands decks).
Complete a specific Champion's legendary win condition — e.g. Nanny of the Maroons wins if she survives 5 rounds after leveling up, or Anansi wins if the opponent runs out of cards. These are difficult but spectacular alternate paths.
Every card belongs to one of six Factions. Players build decks from up to 2 Factions. Each Faction has a unique play identity, visual language, and set of mechanics.
Pirates, sailors, duppy spirits, steelband warriors, and carnival masqueraders. High-speed, chaotic, swarm tactics. Hit fast and hit hard before the opponent stabilizes.
Warriors of Mali, Ashanti, and Dahomey. Griots who buff allies. Amazon soldiers of Dahomey. A slow, powerful, snowballing faction that gets stronger over time.
Escaped enslaved peoples who built hidden communities. Guerrilla fighters, poison healers, and ancestor summoners. Defensive, evasive, and hard to pin down.
Shango, Oya, Legba, Erzulie, Ogun — the Orisha themselves enter the battlefield. Spell-heavy, transformation-focused, and able to manipulate the Spirit Gauge actively.
The oldest inhabitants of the islands. Zemi spirit summoners, sea creature tamers, and shapeshifters. Control-focused with the ability to transform cards and steal unit buffs.
Inspired by the fire marches and uprisings across the Caribbean. Units become stronger when damaged. Martyrdom mechanics reward sacrifice. A burn-and-rise play style.
Every card in a deck is one of five types. Understanding card types is fundamental to deck building and combat.
The most powerful cards. Each Champion is a named cultural figure or deity with unique abilities and a Level Up condition. When the condition is met mid-game, the card physically transforms into a more powerful version with a new ability. Max 6 Champion cards per deck and 3 copies of any single Champion.
Followers, soldiers, spirits, and creatures. They have Power (attack) and Health (defense) values. They attack the opponent's units or Nexus. The backbone of every deck. Up to 3 copies per deck.
One-time effect cards that deal damage, heal, transform units, or manipulate the Spirit Gauge. Spells have a Speed (Slow, Fast, Instant) that determines when they can be played and whether the opponent can respond. Discarded after use.
Placed on the battlefield like a unit but cannot attack or block. Landmarks represent locations — a Crossroads Shrine, a Maroon Village, Mount Olympus Obeah Cave. They provide ongoing passive effects or count down to a powerful one-time event.
A unique Crossroads card type — sacrificed from your hand instead of played. Offerings grant immediate Spirit Gauge charge and a smaller bonus effect. They represent ritual sacrifice and unlock the Orisha Court's Invocation mechanic.
Both players start with 1 Mana Crystal at the start of round 1, gaining +1 each round up to a maximum of 10. All mana replenishes fully at the start of each round. Cards cost mana to play — shown as a number in the top corner of the card. Mana does not carry over between rounds.
At the end of each round, any unspent mana above 0 converts into 1 Spirit Coin (not 1-to-1 — just a flat 1 coin if you had any unspent mana). Spirit Coins are a secondary resource used to activate Faction Abilities — passive powers unique to each faction that cost 1 or 2 Spirit Coins to trigger outside the normal card-play flow. This rewards strategic mana conservation and adds a second layer of resource decision-making.
A shared bar visible to both players, running from 0–10. Filled by: units dying, Offering cards being played, and certain spell effects. At 10, a random Manifestation triggers (based on the current Season setting) and the gauge resets to 0. Both players can see the gauge and plan around it.
Exactly 40 cards — no more, no less.
Cards from a maximum of 2 Factions. You must have at least 1 non-Champion card from each Faction you include.
Maximum 3 copies of any single card. Maximum 6 Champion cards total in the deck (across all Champion cards).
4 cards drawn at game start. Each card may be freely swapped (mulligan) once before the game begins.
1 card per round. If your deck runs out, you take 1 damage to your Nexus per card you would have drawn.
These are concept-level designs to communicate intent to the developer. Full stat balancing happens during development.
When Nanny is summoned, place 2 hidden Ambush units from your deck into the Ambush Zone. All Maroon units gain +1 Health while Nanny is on the battlefield.
When played, deal 3 damage split across all enemy units. Spells you cast cost 1 less mana while Shango is alive. Each time the Spirit Gauge fills 3 points, Shango gains +1 Power permanently.
When Anansi damages the opponent's Nexus, copy one random card from their hand into your hand. Elusive — can only be blocked by other Elusive units.
When a friendly unit dies, Dessalines gains +1 Power (no limit). Rally — grants all friendly units the Undying Flame keyword this round when attacking.
The prototype is not a full game. It is a playable proof-of-concept to validate mechanics, attract investors/partners, and demo at events. Three build phases are outlined below.
These are recommendations — the developer may propose alternatives. The priority is a fast, real-time, browser-first experience with minimal friction to play.
Component-based UI, great for managing complex card game state. TypeScript prevents data structure bugs in game logic.
Global state management for the game board, card hands, health values, Spirit Gauge, and turn phases.
WebSocket layer for live 1v1 play. Supabase offers real-time DB + auth in one platform — good for Phase 2+.
Card play, attack, and death animations. CSS transitions for hover states. Avoid heavy libraries — performance matters on mobile.
All cards stored as structured JSON objects with typed fields: id, name, faction, type, cost, power, health, keywords, description, levelUpCondition.
Vercel for instant frontend deploys, Supabase for backend/database. Both have generous free tiers for prototyping.
Phase 1 uses placeholder art (colored faction-themed SVGs or AI-generated placeholder art). Final art is commissioned separately.
Unit tests for game logic (damage calculation, level-up triggers). E2E tests for core game flow.
The art direction brief for the developer and any UI/UX designers on the project.
Think ritual meets royal. The game should feel ancient and powerful — not tribal in a stereotyped way, but imperial, sacred, and alive. Reference points: the detail of Kente cloth patterns, the dramatic contrast of Haitian Vodou ceremony imagery, the color richness of Trinidad Carnival costuming, the architectural grandeur of Great Zimbabwe and Timbuktu.
Each Faction has a dominant color. Gold and deep black as the universal game chrome. Archipelago: turquoise + magenta. Savanna Kingdoms: burnt orange + deep red. Maroon Highlands: forest green + brown. Orisha Court: electric purple + white. Arawak Deep: sea blue + coral. Canboulay: crimson + ember orange.
One expressive display font with African or serif character for card titles and faction names. Clean humanist sans-serif for stat numbers and card body text. No default fonts — typography is part of the cultural identity.
Each faction's card frame should visually reference its culture: Savanna Kingdoms uses Adinkra-inspired border patterns; Archipelago uses wave and tile motifs; Orisha Court frames glow and shift. The card frame is cultural identity made visual.
The board is the Crossroads itself — a stone intersection overlaid with chalk vévé symbols, lit by fire and moonlight. The Spirit Gauge runs vertically along the center column. Seasons affect the board's ambient lighting (daytime for Harvest, dark and stormy for Hurricane).
Use this as your project brief checklist. Each item should be scoped and priced separately in the developer's proposal.
This document is the primary source of truth for the prototype. Any mechanic not described here should be discussed and approved before implementation. The developer should flag any conflicts between mechanics or feasibility concerns within the first week of engagement.