Tear the earth. Bind the light. Hold the line.

An isometric action RPG in the making: co-op from the first step, a world that remembers, and spells with weight and wonder.

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thaum /θɔːm/ noun

  1. The smallest measure of magic.
  2. An isometric action RPG, cast spell by spell on an engine of its own.

From the Greek thauma, a wonder; whence thaumaturgy, the working of wonders.

A thaum is the smallest measure of magic. We are building a world out of them.

Plate I · The Courtyard

Under the stars, a courtyard that remembers.

Braziers and banners, obelisks and an old well, paving that still holds the rain. This is where Thaum begins: lit by its fires and its spells, wrapped in fog, mirrored in its puddles.

The courtyard at dusk
The courtyard at night
The courtyard at overcast
The courtyard in game · today
  • Volumetric fog that the fires light
  • Light bounced from every stone
  • Reflections in the after-rain puddles
  • Shadows cast by every brazier
  • An image calibrated against Unreal’s

The world’s scars

What a spell breaks stays broken.

When a Gravity Mage tears a slab out of the paving, it stays out, for every player in the world and after the server restarts. Craters keep their rubble. In time the stones are mended, and the courtyard forgets.

drag the seam

The courtyard torn up by a Gravity Mage's fight
The courtyard before the fight
Before and after a fight drag to compare

Plate II · The Constellations

Every class is a constellation.

Base classes, each with a twist of its own: a specialization, a tree of talents and a tree for every skill. Four are lit tonight. The rest are still forming.

The Gravity Mage, concept art

concept art

Gravitas Mage

The Gravity Mage

It doesn’t conjure missiles. It tears up the battlefield.

Slabs ripped out of the courtyard and hurled. Wells that drag foes to their core and catch their shots out of the air. Everything caught feeds the next throw, and what the throw breaks becomes the next well’s ammunition. What it tears up stays torn.

  • Tear and Hurl A slab torn out of the paving, held aloft and lobbed onto the foe. Bigger slabs hit harder.
  • Gravity Well Drags enemies to its core, catches their shots, pulls in the rubble, then flings it all back out.
  • Debris Orbit Five stones circle the Mage, each one taking a shot meant for it.
  • Singularity Torn open at the cursor: everything within seven metres dragged in, then detonated into a crater.

Deep indigo and violet force, starlight specks, and true darkness at the heart

In the game today
The Lightbinder, concept art

concept art

Vinculum Lucis Priest

The Lightbinder

A healer who decides where the light goes.

Threads of light tie a foe to the friend it is fighting: half of all the harm done to the foe, by anyone, heals that friend. Light goes into a friend’s wounds, onto an enemy, or along a thread between the two.

  • Lightbind A lash of light ties a foe to its friend. Harm done down the thread heals, and the thread burns.
  • Radiant Bloom Palms pressed to the earth: a flower of light opens, friends are healed and the ground is blessed.
  • Martyr’s Thread The Priest reaches for a friend and pulls its pain onto itself.
  • Seraph The wings open. Every foe nearby is bound, and for ten seconds the Priest’s healing runs stronger.

Warm white at the heart, gold round it, amber at the edges

In the game today
The Templar, concept art

concept art

Malleus Solis Priest

The Templar

A battle priest who heals by fighting.

Every blow its war hammer lands heals the friends around it, so it stands in the fight instead of behind it. Its light is sunfire, heavier than the Lightbinder’s pale threads.

  • Hymn of Blows Every blow it lands heals each friend within six metres, and the Templar for half as much.
  • Consecrate The hammer driven into the ground: foes on it burn and friends on it mend.
  • Judgment A great leap and the hammer brought down. A hammer of light hangs over everyone it judged.
  • Wrath of Dawn A sun kindles overhead, and a colossal hammer of light comes down out of it.

Sunfire: gold deepening to amber and flame, white-hot only at the edges

In the game today
The Bastion, concept art

concept art

Propugnaculum Warrior

The Bastion

A living fortress.

It plants a tower shield of light whose dome the party fights inside. It swears oaths to its friends and takes their blows, then pays back everything it took as a holy counterblast.

  • Aegis Throw An aegis of light hurled at a foe. It leaps to three more, then flies home through everything.
  • Sanctum A dome of hex light. Friends under it take less harm, and hostile shots stop dead at its shell.
  • Oath A chain of light sworn to a friend: half the harm meant for it lands on the Bastion instead.
  • Citadel The shield raised to the sky, the sword driven into the earth: a great dome, and an oath to every friend.

Azure and silver: domes of hex cells, chains of light

In the game today

Plate III · Spellcraft

Magic with weight.

Each spell is staged like a blow in a fight: it gathers, it strikes, it lands, it lingers. Every effect is drawn by our own engine, so a sky full of them costs a sliver of a frame.

Singularity The Gravity Mage · slowed, in game
  1. I Anticipation Light gathers in the palms and the floor stirs: you see it coming.
  2. II Action The spell does its work: a well opens, a slab is torn, a thread is tied.
  3. III Impact It lands. The flash stays coloured, never washed out to white.
  4. IV Aftermath Dust, grit and stars settle, and the cracks stay where they fell.

The codex

  • 01

    The Gravity Mage

    Singularity

    Torn open at the cursor and held, everything near dragged into its black heart, then detonated.

  • 02

    The Gravity Mage

    Gravity Well

    Opens on the cursor, drags its foes to the core and holds them, crushing, then lets them go.

  • 03

    The Lightbinder

    Radiant Bloom

    Palms pressed to the earth: a flower of light opens under the fight, and the ground is blessed.

  • 04

    The Lightbinder

    Seraph

    A pillar of light, a ring rushing out, and the wings open: every foe round the Priest is bound.

  • 05

    The Bastion

    Sanctum

    A tower shield of light driven into the ground, and a dome of hex light raised over the fight.

  • 06

    The Bastion

    Citadel

    The shield raised to the sky: a circle of runes, a pillar of light, a great dome and an oath to every friend.

  • 07

    The Templar

    Consecrate

    The hammer driven into the ground: the stones crack molten, foes burn and friends mend.

  • 08

    The Templar

    Wrath of Dawn

    A sun kindles overhead, and a colossal hammer of light comes down out of it.

Plate IV · The Night Ahead

Beyond the courtyard, the night goes on.

Three zones are open, each behind its own loading screen on the one server: Thaum Fields, Lantern Square and the Sunken Crypt. More are being forged: ruins torn by the elements, a marsh that glows, wastes where demons walk.

  1. Thaum Fields, concept art
    01 Thaum Fields open Where every hero begins: the courtyard, its braziers and banners, the old compass in the paving.
  2. Lantern Square, concept art
    02 Lantern Square open The hub, where no blade is drawn: a market round a blacksmith’s forge, where every road meets.
  3. The Sunken Crypt, concept art
    03 The Sunken Crypt open A copy for every party that goes down. Where the dead are not resting.
  4. The Dungeon, concept art
    04 The Dungeon forging Down past the falling water, where old sigils still burn.
  5. The Elemental Ruins, concept art
    05 The Elemental Ruins forging Fire, frost and storm let loose among the columns.
  6. The Fungal Marsh, concept art
    06 The Fungal Marsh forging A drowned city, lit by what grows on it.
  7. The Demon Wastes, concept art
    07 The Demon Wastes forging Where the Warlock’s friends come from.

concept art · the zones' loading screens, and the ones to come

The Warlock, concept art

Next to rise

The Warlock

All in on minions: a class whose pack of demons fights at its call, with orders, stances and sacrifices.

A legendary sword rising in a beam of light, concept art

Some blades have names

Legendaries

About eighty named weapons, each with a light of its own and a signature effect when it strikes.

  • Levels, experience, and loot that falls in beams of light by its rarity
  • Forty-nine creatures, first as minions at your side, later as monsters
  • An inventory, and gear worn as items
  • Instanced dungeons, a copy for each party

Plate V · Talents

Write your own stars.

A specialization gives a class its twist. A passive tree, with its branches and keystones, bends it further. And every skill has a tree of its own, whose forms change how the spell plays, and how it looks.

This is the Gravity Well’s tree. Light its stars, and watch the well change.

Gravity Well

or

The well as every Gravity Mage casts it: violet force, a dark heart, stars drawn in.

The game's talent screen: the Gravity Well's skill tree, its White Hole form playing in the live preview
The talent screen in game · the White Hole form in its live preview

Plate VI · Together

Never alone under this sky.

Thaum was built for friends from its first line: a world the server keeps, a party that fights as one, and every one of your own moves felt the instant you make it.

The five classes fighting together in the courtyard, concept art
Five classes, one fight concept art
  • 01

    Parties of four

    Invite with a word in chat: party frames, party chat, a shared target. Five frames when you train.

  • 02

    One world, one truth

    The server decides every hit. Your own hero moves the instant you do, predicted, and is never corrected without reason.

  • 03

    Kept, all of it

    Your character, its look, its build and its bound companions outlive the server going down.

  • 04

    Companions with orders

    Attack, return, stay, change stance: a summoner’s pack listens, and fights the way you tell it to.

  • 05

    A healer’s training ground

    Friendly dummies that bleed, fall and get up on cue, and a meter that keeps an honest score.

  • 06

    By invitation

    Accounts, invite links and a dedicated server: friends play together while it is being built.

The hero is yours

Written in your own stars.

Body and figure, face and hair, an outfit and its colours, dyed to the last thread: the character creator makes a hero that is nobody else’s, and every class has one of its own to begin from.

  • A Gravity Mage, in the game

    A Gravity Mage

  • A Lightbinder, in the game

    A Lightbinder

  • A Bastion, in the game

    A Bastion

  • A Templar, in the game

    A Templar

The character creator: a hero posed, her colours being chosen
The character creator in game

Plate VII · The Engine

Built on Thaum.

Every spark in the footage here is drawn by Thaum, an engine of our own, written in Rust on wgpu. There is no off-the-shelf engine underneath: the renderer, the simulation, the netcode’s logic and the studio the spells are made in are Thaum’s.

a thaum is the smallest measure of magic. Thaumaturgy is the working of wonders.

assets / effects / gravity_well.vfx.ron
// A gravity well while it pulls. The heart: a knot of darkness
// 1.1 m up with a burning violet edge, the world lensed round it,
// an accretion disc sheeting round it. Starlight spiralling in,
// dust dragged across the floor in streaks. Budget: about 330 particles.
(
    name: "Gravity Well",
    emitters: [
        (
            name: "haze",
            capacity: 2,
            space: Local,
            offset: (0.0, 1.1, 0.0),
            spawn: [Burst(count: 1)],
            init: [
                Lifetime(Const(4.0)),
                Size(Const(3.4)),
                Color(Const(0.0459, 0.0216, 0.1674, 1.0)),
            ],
            update: [
                SizeOverLife(Curve(keys: [(0.0, 1.0), (0.5, 1.08), (1.0, 1.0)])),
            ],
            render: [Sprite(order: 0, material: (blend: Additive, ...))],
        ),
        // heart, lens, disc, starlight, dust, stones, reach ...
    ],
)
Effects are data
Systems, emitters and modules written by hand or in the studio, reloaded the moment they are saved.
Compiled to the GPU
Every emitter becomes compute and render shaders. Particles are born, live and die on the graphics card.
A singularity
780 particles, about 0.11 ms of the GPU.
A whole healer’s kit
The Lightbinder’s every effect at once: about 0.04 ms.
The image
A filmic tonemapper and bloom calibrated against Unreal’s own renders, in linear HDR.
The world
Volumetric fog, light bounced from voxels, reflections over probes, shadows from every fire.
The crowd
Hundreds of fighters on an authoritative server, with interest management for a world that grows.

Measured on an RTX 4080 SUPER at the game’s camera, 1920 × 1080.

The night is young

Come and cast with us.

Thaum is played by invitation while it is being built: one dedicated server, a few friends, and new magic all the time.

Ask the friend who sent you here for an invitation.