Small, flightless mantis-kin bred for emotionless warfare, hated by the mantids and nearly extinct through York's hive.
The tenodera are a race of small, flightless mantis-like people, similar enough to The Mantids that the two can crossbreed - which is why most mantids speak openly of exterminating them, fearing what would happen if tenodera mixed with their kind en masse. Tenodera are far smaller and far less aggressive than their cousins.
Their history holds a darker inheritance. Locked deep in tenodera DNA is a numbness their warrior ancestors were specifically bred to carry, from before their people became civilized and fought wars with tanks, bombs and drones - military hardware that replaced the chemicals the queens of old drilled into their soldiers' brains. That absence of feeling was required of any soldier whose duty was to crack open an enemy hive and kill all the children within. York is a tenodera; his entire hive entered the dungeon and was picked off one by one before the Syndicate finished them, and the numbness came for him around the ninth floor. In the epilogue he performs exactly the function his ancestors were engineered for.
Small, flightless praying-mantis-like aliens with mandibles, notably slighter and less imposing than the larger mantids.
York's people, bred for emotionless child-killing and hunted by their larger cousins.