Planar Bestiary
A doom of retribution arises from the planar flux to mete literal doom out against those who trespass against life. Sometimes a doom of retribution acts as a messenger of a coming apocalypse or serves as a literal omen. A doom of retribution—commonly shortened simply to "doom"—targets creatures of the Material Plane, though even fiends and other celestials could find themselves facing a doom in rare situations.
A doom of retribution normally arises spontaneously, but rarely and randomly. A mortal's act of cruelty or violence can call a doom into existence. The newly formed doom's only purpose is to destroy whoever summoned them by their atrocious actions. Even high-level targets have reason to fear a doom of retribution's appearance.
Certain powerful spellcasters and other creatures have learned of the mystical levers of the multiverse. These individuals know a spell to summon dooms and might cast it on their enemies, despite the possibility of blowback. Likewise, ancient artifacts and guarded locations might have the ability to call a doom of retribution should anyone attempt to use the object or access the location.
A doom of retribution usually appears exactly where they are needed, without having to track down their targets. Once called into existence, a doom does their best to slay their target.
A doom is unflinching in completing their objective. They can't be reasoned with or distracted. That said, a doom called through use of a spell capable of summoning them seems to understand the arbitrary nature of their limited existence. Their target might not be a legitimate one, at least as far as the multiverse is concerned. In such cases, a doom of retribution is open to changing their target, but only if the initial target can provide a compelling reason why the creature should do so.
As a celestial being, a doom doesn't require air, food, drink, or sleep.
Some sages suggest that dooms of retribution are a fundamental reflex of the cosmos. Intelligent creatures started using the word "doom" only because of the existence of these entities, not the other way around. However, because of increased crossplanar travel, people in some worlds of the Material Plane are now learning about them as incarnate beings.
Motive: Fulfilling their cosmic purpose to slay their target
Environment: Anywhere they are summoned
Health: 6
Damage Inflicted: Minor wound (3 points)
Armor: 1
Movement: Short
Modifications: Initiative as level 7; Speed defense and perception as level 3; perceives invisible creatures as level 7
Combat: A doom attacks three times each round with their doomblade.
If five or more dooms are present in an area a long distance across, their attacks are eased.
If a doom is killed, 1d6 – 2 additional dooms appear to continue the fight, attacking the first doom's target, whoever killed that doom, or both. This continues each time a doom is killed until there are nineteen dooms in the area (the maximum possible number). Once the doom's initial target is dead (or manages to evade them), more dooms stop appearing.
Interaction: A doom always announces their purpose in a language the target understands. Unless presented with a reason why their target is less preferable than another in the area, a doom ignores attempts to parley or surrender.
Use: A doom appears, ready to punish a PC for a secret deed. An ally or enemy is pursued by multiple dooms.
Loot: A slain doom leaves behind no items or treasure, except sometimes their doomblade (a mundane, if perfectly formed shortsword).
GM Intrusion: The doom senses a weakness in the character's defenses, easing their own attack by four steps and inflicting an additional moderate wound (4 points).