Routing is when units retreat from combat without being ordered to. This may occur due to a failed a morale check (e.g. versus Fear, taking damage, ), or simply because enough of their army has died or retreated to trigger an HP rout.
Units that are Mindless or have Gone Berserk cannot rout. Anything else can, even if it has very high Morale, though the conditions that might cause them to rout can vary.
Routing units rush to their end of the battlefield, to try and get out as quickly as possible. While doing so, they suffer from a -4 Defence Skill penalty, making them easier for enemy units to hit.
Even if routing units successfully retreat from battle, persistent effects such as Poison Damage, Profuse Bleeding, or Decay remain in effect. 100 rounds of these will be calculated off-screen, which can result in the routed unit's death post-battle.
Even if the battle was won, units who rout will retreat from the province. The manner in which they retreat depends on whether their Commander also retreated.
If their Commander DOESN'T rout in the same battle:
If their Commander DOES rout in the same battle:
The most common sort of rout happens by squad. The standard Morale roll applies here: if that's failed, the whole squad routs, though perhaps not the Commander leading them. The Morale roll for this one can only take place once per combat round (per squad).
What triggers a Morale roll of this caliber?
Once the total HP value of the whole army is under 50% of its maximum, all other triggers are ignored: as long as the army's total HP is that low, each squad is hit with the standard Morale roll each combat round. This counts those who have already retreated as still being a part of the army, but having zero HP. Once the total HP value of the whole army is under 25% of its maximum (with the same conditions), the entire army (discounting the exceptions mentioned at the top of the page) routs right away: this is known as an HP-rout.
Many varieties of troops count less towards Army HP than the average soldier:
If the rider of a Mount dies, the Mount might individually rout.
If the rider routs individually, or if the whole squad/army routs, the two ride off together. If the Mount routs individually, or if they both individually rout from the same effect, the Mount bucks the rider off. Dismounting in this fashion causes Armor-Negating damage equal to the Size difference between the two (Mount-minus-rider), complete with a DRN. Some Mounts don't cause this damage, though; all of them are Chariots.
At Turn 150, everyone with 50 Morale or lower in the attacking army routs. At Turn 170, everyone with 50 Morale or lower in the defending army routs. This is known as a turn-rout.
If there are no Commanders of the correct Leadership type – Undead Leadership for Undead and Demons, Magic Leadership for Magic Beings, or regular Leadership for everyone else – then everyone who needs that Leadership type will rout unless they have 99 Morale. Illusions are a special case, requiring one of the Commanders to have either a level of Glamour magic or the Glamour Manipulator trait.
Beings with 50 Morale are Mindless. This means they don't really rout; instead, they stop fighting entirely and gradually disappear from the battle. They only do this through either the lack of Leadership or the turn-rout.
On another note, beings with 30 Morale only rout due to either the lack of Leadership, the HP-rout, or the turn-rout.