<p>I don't think the biome should change at all, however, maybe orc spawning could be enabled if there is area claimed by that faction, connected to their own biome.
For example, if someone bannered large area (with mordor banners) from the border of Ithilien, and the claim reaches the lands of Mordor.
</p><p>Not sure what I think of the idea, but at least it needs to be improved and clarified.
A bit of grammar doesn't hurt either
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