The Iron Sepulcher is Standard of Iron's undead faction. It has no economy, recruitment loop, or player-selectable slot. Undead troops reach the battlefield through undead zones authored on the map: dormant sites that awaken, raise a garrison, and turn part of the terrain into a temporary strategic problem.
The system is data-driven through undead_zones in map files and implemented by Game::Systems::UndeadAwakeningSystem.
A zone can define its trigger, guardians, haze, reward, and decorative anchor:
"undead_zones": [
{
"id": "shrine_sentinels",
"anchor_type": "magic_shrine",
"x": 33,
"z": 16,
"radius": 7.0,
"leash_radius": 12.0,
"owner_id": 99,
"team_id": 99,
"awaken_on": ["unit_enters_radius"],
"fog_density": 0.28,
"clear_reward": { "gold": 150, "stone": 80 },
"waves": [
{ "trigger": "initial", "units": { "skeleton_swordsman": 2 } },
{ "trigger": "after_clear", "units": { "skeleton_archer": 3 } }
]
}
]
| Field | Meaning |
awaken_on |
unit_enters_radius by default, or mission_start |
waves |
Optional wave definition; omitting it uses the default garrison |
anchor_type |
Decorative prop around which guardians rise; it does not determine whether a shrine exists |
fog_density |
Optional zone haze; 0 disables it |
clear_reward |
Optional one-time resources granted when the garrison is broken |
owner_id is a real owner registered as an AI player of nation iron_sepulcher. That nation resolves to the sepulcher_defense AI profile.
clear_reward is paid once when the garrison breaks, whether the shrine is captured or destroyed.
If the shrine is captured, the reward goes to its new owner. If it is destroyed, the reward goes to the local player. Resources are added as spendable balance rather than through the harvested-resource path, so clearing a barrow can finance the next push without accidentally satisfying an accumulate_resources objective.
This is the intended role of an undead zone: it is optional, dangerous ground that can be worth contesting. Every mission in the Second Punic War campaign contains at least one.
A zone with no waves entry raises the default garrison in one wave:
An authored waves list replaces the default completely; the two are never merged.
A wave rises in a single simulation tick. Guardians are distributed on a golden-angle sunflower spiral across the zone radius so they emerge around the anchor rather than stacked at one point. Invalid or impassable positions are skipped.
During configure(), every undead zone is paired with exactly one magic shrine. The map does not need to author that shrine and cannot opt out of it.
Game::Map::plan_undead_zone_shrine in game/map/undead_shrine_placement.h chooses the location in three steps:
configure()—for example after reload or Arena restart—to find the same shrine instead of creating another.A newly created shrine is inserted into the terrain service as a real world prop, which makes it part of both rendering and save/load state.
At the shrine, the system creates a Barracks entity that acts as the gameplay anchor for capture, destruction, health, navigation, and ownership.
The anchor:
iron_sepulcher;ProductionComponent, so it can never recruit; andThe building renderer troops/iron_sepulcher/barracks submits no visible barracks geometry. The shrine itself remains a terrain-scatter prop, so the physical shrine and the capturable entity occupy the same site without drawing two structures.
If no valid shrine location can be found—for example, because a zone was authored entirely inside a lake—the system logs the failure, creates no barracks, and exposes the zone through zones_without_shrine().
content_validator runs the same placement logic against every shipped map and fails when a zone cannot receive a shrine.
The garrison breaks when the shrine building is destroyed or changes owner.
At that point:
This feeds directly into the normal victory system. Objectives such as clear_undead_zone and purify_shrine need no special-case mission logic beyond the state published by the undead system.
Other anchor_type values remain decorative. They influence where guardians appear, but they do not replace the mandatory shrine.
A zone with positive fog_density contributes a light, translucent FogZone sized to its radius and rendered on the CPU by AmbientFogRenderer.
Fog patches include a ground height. The map owner—such as the skirmish loader or Arena—projects the patch onto the terrain before sending it to the renderer so the haze follows raised ground instead of sinking beneath it.
UndeadAwakeningSystem publishes Engine::Core::MissionAnnouncementEvent, which GameEngine forwards to the existing mission-announcement toast.
Each zone announces each event at most once:
serialize_state() and restore_state() preserve the runtime state needed to resume an active zone:
The shrine barracks itself is an ordinary entity, so its health and owner are serialized with the world.
On load, configure() runs again and adopts the shrine already present in the restored terrain state. restore_state() then reconnects the zone to its existing barracks and live guardians. A restored save therefore neither duplicates the shrine nor replays an already active wave.
The system is tested at several levels:
tests/systems/undead_awakening_system_test.cpp covers wave behavior, defaults, spawn spread, shrine anchors, one-shrine-per-zone rules, blocked and impossible placements, garrison break, announcements, and save/load.tests/map/undead_shrine_placement_test.cpp tests the placement algorithm directly and sweeps all shipped maps to ensure every authored zone can receive a shrine.tests/map/iron_sepulcher_skirmish_test.cpp exercises the complete skirmish-loader path, including awakening, purification victory, capture, and destruction.sepulcher_* scenarios documented in tools/arena/README.md.The resulting design keeps the Iron Sepulcher deliberately outside the normal economy: undead presence comes from authored places in the world, and defeating that presence is expressed through capture, destruction, and ordinary mission objectives rather than a parallel game mode.