They could try to come to help stop the destruction and repair the damages afterwards; like I mentioned, this isn't a conquest battle, but a destruction one. The Mayhem Riders are here to destroy the Green City. That's just the first half of the "Burn the woods" plan that he has. I want Arms Slave and Tender Fern to parley a bit first before Dark Wraith shows up to fulfill the "Salt the Land" second half of the plan.