Concordant Killer

This creature resembles a tall, scarlet-skinned fiend with a pair of dusky feathered wings. Its loose-fitting robes are decorated with polished bits of blades taken from fallen enemies, and a grey-indigo vapor rises from the top of its head.

Perfectly Balanced. Possessing both celestial and demonic heritage, the concordant killers are beings of pure neutrality. Some say concordant killers were an experiment by gods of neutrality, who sought to create the perfect stewards for maintaining the cosmic balance. Others hold that they were created by a long-forgotten demigod to serve as bodyguards. It is theorized that, whatever their original purpose, they failed in that endeavor, and their master was lost to a cosmic rival. Left without direction, they settled into the role of mercenaries. Whatever the truth, as beings of neutrality, concordant killers are concerned with the balance of all forces in the planes. They understand that defeating a powerful foe might tip the scales one way or another. Therefore they track their kills as a group, endeavoring to distribute their prey evenly among the the forces of the multiverse. . They keep the location of such meetings secret, though many sages believe they congregate near the central spire of the Outlands. Even deities’ magic is impeded there, making it a perfect spot for clandestine gatherings.

The Last of Their Kind. Concordant killers do not reproduce, so every one that falls in battle forever reduces their number. Anyone who destroys a concordant killer inevitably becomes the target of its irate and vengeful kin. They exist in their current state to hunt down and destroy other powerful creatures. Effective yet discreet, they are highly sought after by powerful entities such as demon lords, demigods, and even deities to do their dirty work. A concordant killer is dismissive of any prospective employer, though, unless offered substantial payment.  Concordant killers trade their services for favors, having little need for material possessions. Sometimes they request these favors at the time of hiring, but usually a contract for future payment suffices. Even gods are indebted to the concordant killers and so might look the other way, leave a planar portal open, provide information on a target’s whereabouts, or undertake other favors that help the killers achieve their objectives. In the case of a recent death among their ranks, the favor may include the resurrection of a fallen comrade. 

Immortal Nature. A concordant killer doesn’t require food, drink, or sleep.

Based on the work of Dungeon Dad on YouTube to convert 3.5e monsters to 5e.