Pretty much all samurai women got some basic training in the naginata and were expected to protect their homes when their husbands were off in military campaigns. Tomoe Gozen is seen as the ideal, as she was one of the very few women who not only actually participated in field battles, but was also a military commander. She has a contemporary Hangaku Gozen who is known for the same, but she's less well known purely because she fought for the Taira who were on the losing side of the conflict.Well, the Feudal Japanese treating them well would have made sense, but certainly not the Mongols. As for women leading and negotiating on behalf of the Japanese that would make sense, though I'm not familiar enough with that era to know if they would have been present at Tsushima. There was actually a pretty famous female samurai by the name of Tomoe Gozen in the Genpei War which was occurred shortly before the Mongol invasions. It wasn't that horribly uncommon for noble females to receive martial training during the more chaotic periods of Japanese history since it was not uncommon for all of the male family members to be deployed elsewhere.
The Mongols were likely the world leaders at that time in sex slavery. Many of the males in the Khan family had 100s of wives.
Afterwards there were quite a few warrior women in the Sengoku period, like Kaihime and Myorin, but they only participated in defensive siege battles, as it was expected of warrior women of the time. Women who had a lot of influence in the Sengoku period weren't the ones who were warriors though, but ones who were very skilled in politics and diplomacy, like the mother of Imagawa Yoshimoto Jukei-ni and Maeda Toshiie's wife Matsu.
Now I know what you're thinking, what the fuck does the Sengoku period have with this? Well, clearly, the game takes influence from both, since the Sengoku period is much more well known they sprinkled in a lot of stuff from there as well.