Hachi is Sadao's brother and runs supply carts between camps. In The Headman, Jin and Masako follow his cart to find Sadao, and in The Husband he tries to free Sadao's wife Hina.
When the bandits stop him, the trail splits: they let him go and you follow the bandits. Later Hachi is ordered to kill Hina, panics when she screams and kills her. Mongols wound him as he flees.
Jin and Masako kill the Mongols. Hachi says he only wanted to save Hina, then dies. His papers lead them to Sadao.
Hina
Hina is Sadao's wife. Masako and Jin take her to the Adachi Estate for questioning in The Husband. She is scared of Masako and much more willing to talk to Jin.
Masako Adachi
Lady Masako Adachi is the only survivor of Clan Adachi and one of Jin's allies. Her husband and sons die in the Mongol landing and the rest of her family is murdered the same night. Her side storyline, Masako's Tales, has you hunting the people behind that massacre.
Sadao
Sadao used to run Kuta Farmstead as headman and is one of the Adachi conspirators. He was removed after hoarding rice and having protesters killed. He hides at Ariake Lighthouse while Masako and Jin work their way to him through his family.