Tertians were the second-most powerful type of hierarch modrons.


Tertians were very tall humanoids, with a height of 12 ft (3.7 m). They had a prehensile tail that acted as a third arm, at the tip of which was a growth that was similar to a mace. A tertian had a ring of horns that encircled their hairless head.[2]


If forced into combat, a tertian will use a combination of innate abilities, spells, tail and fists.[2]


Like all hierarch modrons, tertians had the innate ability to duplicate the effects of clairaudience, clairvoyance, command, dimension door, teleport without error, and wall of force spells at will.[5] Tertians were able to cast arcane spells as well as divine spells from the Law, Protection and War domains. Tertians were immune to all effects that influenced the mind, all psionic-based attacks and had a resistance to acid, cold and fire.[2]


They acted as judges, judging and sentencing both modrons and non-natives.[3][1][2] Nine tertians existed, with eight of them reporting to the Secundi, and the final one reporting to Primus himself.[3][1][2]


Tertians were able to communicate telepathically with any sentient creature within 405 mi (652 km) and could see in darkvision up to 60 ft (18 m).[2]




The Great Modron March


  1. 1.0 1.1 1.2 1.3 David "Zeb" Cook (1994). Planescape Campaign Setting, Monstrous Supplement. Edited by David Wise. (TSR, Inc), pp. 16–20. 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 2.12 Mark Jindra (2001-09-21). The Modrons (Zipped PDF). Wizards of the Coast. pp. 16–17. Archived from the original on 2016-11-01. Retrieved on 2018-09-09.
  3. 3.0 3.1 3.2 Gary Gygax (August 1983). Monster Manual II 1st edition. (TSR, Inc), p. 91. ISBN 0-88038-031-4.
  4. Mark Jindra (2001-09-21). The Modrons (Zipped PDF). Wizards of the Coast. p. 2. Archived from the original on 2016-11-01. Retrieved on 2018-09-09.
  5. Monte Cook, Colin McComb (1997-10-28). The Great Modron March. Edited by Michele Carter. (TSR, Inc.), p. 126. ISBN 0-7869-0648-0.


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