Tridrones were an intermediate type of modron.[2]


Tridrones were shaped like inverted tetrahedrons and were capable of performing three tasks at a time.[2]


Like all modrons, tridrones had an absolute sense of hierarchy and order, and could not be persuaded to disobey their instructions or betray their purpose in any way.[2]

It was possible, however, for a defective tridrone to go rogue and start acting in its own interests or no longer in accordance with its instructions, sometimes even becoming violent. Such rogues were relentlessly hunted by other modrons, although, unlike their properly operating fellows, they could be reasoned with.[2]


Tridrones were capable of wielding weapons and were competent combatants, capable of performing three attacks at a time. If destroyed, a tridrone disintegrated completely into dust and a duodrone was instantly upgraded into a tridrone to fill its position.[2]


Like all modrons, tridrones were immune to all effects and spells that influenced the mind, fear and attacks that rely on energy from either the Negative or Positive energy planes. They also had a resistance to acid, cold and fire.[6]


Tridrones could communicate with other tridrones and with duodrones and quadrones. They were incapable of communicating directly with monodrones and could not comprehend the more advanced pentadrones.[2]

In modron society, tridrones were responsible for leading groups of lesser modrons into battle. They were always created as the result of upgraded duodrones to take the place of destroyed units.[2]

There were about six million tridrones in modron society.[7]


Sometime in the late 1480s DR, a tridrone leading a group of monodrones was stranded in the Labyrinth in the Underdark, separated from the other modrons since the previous Great Modron March, over two centuries earlier. After years of wandering, the tridrone managed to keep the group together, but felt responsible for its failure in performing their assigned task.[8]



Out of the Abyss[8]The Great Modron March
Evil at Baldur's Gate #3
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  1. 1.0 1.1 David "Zeb" Cook (1994). Planescape Campaign Setting, Monstrous Supplement. Edited by David Wise. (TSR, Inc), pp. 16–19. ISBN 978-1560768340.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Wizards RPG Team (2014). Monster Manual 5th edition. (Wizards of the Coast), pp. 224–225. ISBN 978-0786965614.
  3. Brian James (August 2012). “The Ecology of the Modron”. In Steve Winter ed. Dragon #414 (Wizards of the Coast), p. 12.
  4. Mark Jindra (2001-09-21). The Modrons (Zipped PDF). Wizards of the Coast. p. 8. Archived from the original on 2016-11-01. Retrieved on 2018-09-09.
  5. Gary Gygax (August 1983). Monster Manual II 1st edition. (TSR, Inc), p. 88. ISBN 0-88038-031-4.
  6. Monte Cook, Colin McComb (1997-10-28). The Great Modron March. Edited by Michele Carter. (TSR, Inc.), p. 126. ISBN 0-7869-0648-0.
  7. Gary Gygax (August 1983). Monster Manual II 1st edition. (TSR, Inc), p. 86. ISBN 0-88038-031-4.
  8. 8.0 8.1 Christopher Perkins, Adam Lee, Richard Whitters (September 1, 2015). Out of the Abyss. Edited by Jeremy Crawford. (Wizards of the Coast), pp. 179–180, 183–184. ISBN 978-0-7869-6581-6.


Mechanical Beings of Inherent Order
Base Modrons: MonodroneDuodroneTridroneQuadronePentadrone
Hierarch Modrons: DecatonNonatonOctonSeptonHextonQuintonQuartonTertianSecundus
The One and the Prime: Primus
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