To be fair S-rank, should really have seen this coming sooner. Though I still do not understand I pods involvement, they do not get anything good out of it.
But if you block off a tribes entire expansion to the rim, and essentially box them in, what other choice do they have. And they would find it difficult to win without bringing in other tribes from the rim. To hit their back line.
What's more the rim tribe are all to happy to take advantage, 1 because they get some nice easy villages (maybe) and 2 S-rank tried to spread into a many Ks in preperation for taking them all over at once. So have spread yourself too thin.
They might still be able to win on all fronts, but not it comes down to the individual skill of each player, they will need to snipe, retake and dodge everything.
Good luck, interesting war
side note just checked out Floss, and it looks like s-rank has been attacking them since before Christmas, so defiantly brought that on yourself.