Ethnos
Must you empty your Orc Horde board at the end of an Age?
The Orc section makes pillaging optional and describes what it clears.
- Ethnos rulebook · Rulebook · Tribe of Orcs
No. Emptying the Orc Horde to pillage is optional. If you pillage, you score Glory for the markers removed; if you leave the markers, they stay and can score more in a later Age.