Parameters
- King / pool
- King of Blood
- Card type
- Building
- Mechanic
- Summons demons and strengthens them as allies die or troop plots are destroyed; Patch 30 increased its scaling.
- Trigger
- Battle summoning / allied deaths / troop-plot destruction
- Affects
- Demon summons
- Placement rule
- Death scaling is not described as an adjacency-only trigger
- Documented effect
- Unverified
- Effect unit
- Unverified
- Version checked
- Patch 31 / 0.9.8
- Earlier name / replaced card
- Demon’s Altar (renamed Patch 29)
- Base HP
- Unverified
- Base damage
- Unverified
Overview
Demon Altar is the Blood building that summons demons and develops them through allied deaths. The current name is Demon Altar; Patch 29 removed the possessive from Demon's Altar. Its scaling changed again in Patch 30, so an old percentage copied from a pre-rework card table should not be treated as the current damage model.
Death and destruction are useful triggers
The official Wiki establishes demon summoning and permanent growth from allied deaths. Patch 18 expanded its interaction with destroying troop plots. These are distinct sources of growth: casualties during a battle and deliberate destruction decisions before combat should not be collapsed into a single assumed event count.
Patch 30 doubled damage gained from unit deaths and increased level-up benefits. It also changed how the tooltip communicates the buff, using a raw bonus instead of the older percentage presentation. A smaller displayed number after that update is not automatically a nerf. Because the complete final calculation is not published, this catalogue leaves base damage unknown and does not reconstruct an exact late-game result.
Assemble a death engine that still wins battles
A death-oriented build needs units that can die, demons that can use the growth, and enough immediate pressure to protect the base. Oblation increases troop populations through the pit, providing one possible source of bodies. Mangler produces meat-troll summons and uses adjacent-unit sacrifices. Cemetery replaces eligible neighbouring casualties with skeletons. Each card has a specific trigger and placement rule; sharing a Blood theme does not make those rules interchangeable.
Place support only after identifying the essential combat recipient. If a deliberate destruction removes the only defender, the later demon growth may arrive too late to save the next battle. Keep the distinction between “more triggers occurred” and “the remaining army became able to win.”
Read current summons correctly
Cemetery summons Skeletons, Pagoda summons Ghosts, and Mangler launches meat trolls after the relevant reworks. Old guides describing every Blood summon as an Imp no longer identify the recipient correctly. This matters when a perk or decree names a specific card or summon.
The official Wiki uses the Building type for Demon Altar. Older databases may use a Tower label. This reference follows the official type and marks unsupported current combat values as unknown; the discrepancy is a reason to inspect the in-game compendium, not a reason to invent a hybrid type.
A practical verification checklist
Record the Altar level, current displayed stats, the casualty or destruction event, and the new stats. Test a single relationship before layering several engines. That makes it possible to notice a version-specific result without claiming that every combination has been measured. Do not use a pre-Patch 30 tooltip screenshot to establish current scaling.
Version and sources
Mechanics were checked through Patch 31 / 0.9.8. The Patch 29 rework and Patch 30 balance changes take precedence over the older Wiki numbers. Compare the summon and death triggers in the card database.