As Saberteeth worked out the details with the mayors to get their support for the relief effort at the capital, he was also writing contracts for them to draft manpower for the Demon Rat Offensive. Since Jin had been able to get the Southern Leader on his side, he might as well play bigger and mobilise the entire Southern Region.
That way, not only would it make the Demon Rat Offensive slightly easier, it would drastically increase the production of the items he wanted to make in the future, if he had ended up with two major regions under his control.
However, the mayors were a little skittish on the fact that Saberteeth was giving their recruited men off for training, islands away from the Southern Region. All these were once again orchestrated by this secret organisation, just called the 'P".