Witness-Blood Altar
The Witness-Blood Altar is a dormant ritual engine hidden in the ruins of a desecrated shrine. It does not spring like a mechanical trap. Instead, it turns the room into a momentary echo of the cult's last ceremony, forcing intruders to reenact its violence. The altar rewards hesitation and careful investigation, but punishes anyone who treats the chamber as ordinary rubble.
Witness-Blood Altar
Defenses
Detection
“A cracked stone altar stands within a ring of black candle stubs. Four shallow channels carved into the floor converge on a tarnished silver bowl. The bowl is always wet with fresh-looking blood, though no source can be found. When the hazard stirs, the ruined walls briefly resemble kneeling worshipers.”
Standard Engagement
The hazard triggers when a living creature touches the silver bowl, crosses the ring of black candles, or removes an object from the altar. It also triggers if a creature pours blood into the bowl without using the reverse prayer.
On initiative count 20, the altar emits a low chant. Each creature within 10 feet of it must succeed on a DC 14 Constitution saving throw or take 2d6 necrotic damage. The altar then chooses the creature that has taken the most damage from the hazard. That creature must succeed on a DC 15 Wisdom saving throw or be pulled up to 10 feet toward the altar, stopping in the nearest unoccupied space. The routine ends after the second initiative count 20.
The altar resets after 24 hours if its candles remain intact and at least one blood channel has not been disrupted. If the altar is suppressed but not disabled, the candles relight and the bowl refills with blood.
Each creature in the chamber when the hazard triggers must make a DC 15 Wisdom saving throw. On a failed save, the creature is frightened of the altar until the end of its next turn and takes 3d8 psychic damage. On a successful save, it takes half as much damage and is not frightened.
A creature that starts its turn within 10 feet of the altar while the hazard is active must succeed on a DC 14 Constitution saving throw or take 2d6 necrotic damage as a spectral ritual knife cuts across its palm. A creature can willingly take 1 hit point of damage to automatically succeed on this saving throw.
A creature that willingly spills at least 1 hit point worth of blood into the silver bowl gains advantage on its next saving throw against the altar, but the altar marks that creature until the next dawn. While marked, the creature has disadvantage on saving throws against the altar.
The altar's magic cannot pass through more than 1 foot of stone, 1 inch of metal, or a thick wooden door. Total cover protects a creature from the altar's effects.
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