Battles don't last forever. Even in a stalemate – say, a slow-killing thug up against Horde of Skeletons casters – the battle will be forced to end. The turn timer helps battles end through three thresholds:

You can see the current combat turn by pressing ctrl+c in battle. At turn 90, all units on the attacking side rout immediately, if they are capable of routing. Mindless and currently berserking units do not rout. At turn 110, the same happens to the units on the defending side. If the battle has not ended by turn 150, all units die immediately.

Immortals who die this way will respawn normally, as if they had died by any other non-soul slay cause.

The turn timer is reached when neither army is able to fully kill or rout the other for a very long time. Given this requirement, there are several scenarios through which the turn timer can be practically reached:

• A durable thug or insufficiently killy supercombatant fights against an army that can easily generate large amounts of chaff (e.g. Horde of Skeletons casters). The chaff will not be able to kill the thug, and the thug will not be able to clear the chaff before the mages recover their fatigue and summon more chaff.
• Either side casts Rigor Mortis and/or other fatigue plays and everything falls asleep before they can kill their opponents, or the remaining resistant units are insufficient to kill their opponents. See oops (itsmu) for an example.