Great Modron March
The Great Modron March is an event that occurs once every Great Cycle (a period of time equal to 289 years, or 17 cycles of the largest gear of Mechanus, each one taking 17 years). During this time, a horde of over 10,000 modrons emerges from the gate of Automata, making its way around the Great Ring until eventually returning to Mechanus, usually numbering a mere few dozens upon its return. Though the specifics behind the purpose of this event are unknown, most believe it to in some way involve the collection of information from across the planes. The method of their collection, however, remains a mystery, as they never seem to ask questions or collect samples, merely march and observe.
Though predictable, this event is still quite hazardous to those in its path, as the modrons simply cannot be reasoned with. Though agreements have been made about the chosen path between marches, once the march begins they cannot be diverted from the path that has been determined for them before their outset. Entire towns have been known to be crushed underfoot as the modrons make their journey through the planes, not to mention the individuals who have suffered the same fate.
The general route of the Modron March has been fairly well recorded over the centuries, though the specific path they choose to take during any one march tends to vary a bit, never following the exact same course. Most believe that the best path for a given year is chosen for them to take before they leave, though the characteristics of "best" are unknown.
Though attacks on the March are common, they're rarely successful. The March may be susceptible to quick hit-and-run tactics, but once prepared for the fight, they're a well-ordered fighting unit, able to repel all but the most deadly of threats. Modrons, being creatures of pure law, are never cruel nor merciful in their defense of the march, merely cold and logical.
When on the March, modron death is met with promotion from within the ranks of the March. Thus, the monodrone forces are the first to be depleted, followed by the duodrone forces, and so on up the hierarchy. This ensures that those who finally reach the end of the March to report back to Primus are the highest-ranked modrons of the group, even if they may not necessarily be the same superiors that started the voyage.
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