In Active Development

Command the Empire.
Defend the Golden Horn.

A medieval castle-building RTS simulation set in the turbulent Komnenian Byzantine Empire. Construct multi-tier Theodosian walls, master Mediterranean logistics, and unleash devastating Greek Fire against ruthless siege armies.

Core Gameplay

Command, Build & Conquer

Fortification

Theodosian Fortifications

Design and construct authentic multi-tier Byzantine defensive networks with complete architectural freedom. Erect low outworks, deep moats, and colossal curtain walls reinforced with bastions and sortie gates.

Secret Weapon

The Secret of Greek Fire

Turn the tide of impossible sieges with the empire’s closely guarded incendiary weapon. Deploy bronze siphon batteries, parapet cauldron traps, and incendiary dromon war galleys against invading armadas.

Logistics

Living Medieval Economy

A fortress is only as strong as its granaries and armories. Establish organic Mediterranean supply chains from rural wheat estates and windmills to iron mines, armor smithies, and alchemical refineries.

Warfare

Field Command & Formations

Command versatile Byzantine legions—from disciplined Skoutatoi infantry in phalanx lines to heavy Cataphract cavalry and elite Varangians. Master defensive bottlenecks against adaptive AI warlords.

Tactical Showcases

Battlegrounds of the Empire

Maritime Defense

The Golden Horn Boom Chain

Hold the harbor entrance against invading naval armadas. Deploy incendiary dromon squadrons behind the massive iron boom chain.

Fortress Defense

The Siege of Constantinople

Defend the triple Theodosian land walls against overwhelming siege towers, sappers, and counterweight trebuchet bombardments.

Frontier Warfare

Anatolian Mountain Keeps

Establish fortified mountain passes and supply redoubts along the rocky frontier to repel agile raiding parties and secure border settlements.

Technical Foundation

Engine & Platforms

Deterministic Core

Built on custom tick-rate lockstep architecture ensuring 0 desyncs and bit-exact simulation.

Target Platforms

Native 64-bit support for Windows, Linux, and seamless Steam Deck compatibility.

Modding & Scenarios

Data-driven architecture designed for custom campaigns, maps, and community assets.

Behind the Scenes

Developer Updates & News

Follow the Studio Devlogs

Deep dive into the making of Byzantine Fire. We regularly unveil new units, siege mechanics, architecture, and procedural assets on the Castellan Studios developer portal.

Read Studio Devlogs