The tidbit about the "lands to the west" is really intriguing to me since the only lands we've heard about are Islabad, Othard, and the "island continent" to the far south. So they're coming to Eorzea as mercenaries, in the Arcanist guild there is a Mamool Ja patiently waiting in line to retrieve his belongings from the customs agents. Dodozan is an Ul'dahn merchant in Limsa Lominsa and he praises Limsa for having not given the Beastmen the boot like Ul'dah has.

Edit: so the Mamool Ja are coming to Eorzea to fight.