if its your first time, usually after one loss, eventually after raising myrina's affection and possibly also part of your govenrment Antiope would come back to reclaim her lover.., youll be faced with a scripted attack, which will not actually end in combat if you have raised her affection..,
later on youll face a duel.., which ends with another futamazon as a slave/follower..,
after that another scenario appears, once taking one piece of land(random though) from the futamazons, youll also get a scripted event with various outcomes.., which also nets you another futamazon as a slave/follower..,
but the actual event that ends all of this is a scripted event that usually appears after you have taken the control of those in charge.., the event entails you getting attack by some futamazons but they failed, they are given a tour of your nation. and thus they all give up fighting and align themselves to you..,
edit: asides that there really isnt much to say or do.., just fight, or reroll a save.., in this game, if you conquer or obtain opposing factions into your nation by alternative means you also gain their land, and a larger building area around their capital instead of the usual 4-8 buildable squares from normal territory conquering..,