Supervisor (Decaton) Large construct, lawful neutral Armor Class 18 (natural armour)

18 (natural armour) Hit Points 130 (20d10 + 20)

130 (20d10 + 20) Speed 40ft., fly 40ft. (hover) STR DEX CON INT WIS CHA 16 (+3) 15 (+2) 12 (+1) 10 (+0) 10 (+0) 14 (+2) Skills Perception +8

Perception +8 Condition Immunities prone

prone Senses truesight 120ft., passive Perception 18

truesight 120ft., passive Perception 18 Languages Celestial, Infernal, Modron, telepathy 120 ft.

Celestial, Infernal, Modron, telepathy 120 ft. Challenge 10 (5,900 XP) Axiomatic Mind. The supervisor can't be compelled to act in a manner contrary to its nature or its instructions. Disintegration. If the supervisor dies, its body disintegrates into dust, leaving behind its weapons and anything else it was carrying. Actions Multiattack. The supervisor makes six tentacle attacks. Tentacle. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) slashing damage. Attack Directive. The supervisor telepathically commands up to six allied targets. Each target uses its reaction to attack the nearest enemy creature and deals an extra 1d6 damage on its first hit. Eye Rays. The supervisor fires up to all three of the following eye rays choosing up to six targets (two for each ray) it can see within 120 feet of it. Disintegration Ray. The targetted creature must succeed on a DC 14 Constitution saving throw or take 36 (8d8) force damage. If the target is reduced to 0 hit points by this damage, its body is reduced to a fine grey dust. Petrification Ray. The targeted creature must make a DC 14 Dexterity saving throw. On a failed save, the creature begins to turn to stone and is restrained. It must repeat the saving throw at end of its next turn. On success, the effect ends. On failure, the creature is petrified for 24 hours or until freed by greater restoration or other magic. Vitalization Ray. The targeted construct regains 10 (2d6 + 3) hit points and gains an equal amount of temporary hit points. Additionally, the target deals an extra 5 (1d10) lightning damage to targets it hits with melee attacks before the end of its next turn.

Image Credit: Jeff Easley (Planescape Monstrous Compendium Appendix (2e))

Sometimes incorrectly referred to a hexadrone; the modron supervisor isn't a drone at all but one of the upper hierarchy of modrons, above common drones. Their proper name in Modron translates as one of the tenth rank or decaton for short. They are the lowest of the ruling classes of modron, yet still far more powerful than the common drone counterparts.

There are exactly one hundred supervisors in service to the modron Primus at any time; sixty-four of which are labor supervisors on the Modron homeplane of Mechanus; the remaining thirty-six serve in the army, each serving as the commanding officer of a sizable platoon of drones [MM 224-226].

Usually only seen on the prime material plane if they're actively at war or seeking the arrest of a criminal, who broke celestial and/or infernal laws severely to bring them back for trial in Mechanus. Their usual battle tactics are to hide behind waves of their soldiers while attempting to disable the opponents with their magic to facilitate their arrest or help their underlings more easily defeat them. They only proceed into melee when absolutely necessary.

As for their structure; it is unknown if the Primus attempted to make a mechanical version of a beholder to serve in his armies or if the similar design was simply coincidental. Supervisors use a mechanical means to magnetically float and can hover endlessly in the presence of any natural or magical magnetic field or sufficient metal to repel against. They also have additional thick legs that support their body should they find themselves unable to hover for any reason. These legs fold up inside their chassis while hovering.