House Sung was a noble house in the Forest of Chin. Lijuan was raised as a servant of this house until House Zhen contrived to take over, legally and violently. (The general story told now is that the two houses were feuding, and House Zhen won and was granted House Sung's lands, but there was probably more to it than that). Keep Sung is now ruined (Defeated, in the technical sense) and thought to have ghosts. In the ruins we found House Sung Documents.
There's a rumor that an heir to the house escaped the carnage. Zhu Cai Wen and Deng Zhi-Hao may have convinced the Warlord's Armsmaster that this heir is dead. They may have convinced House Tsai that House Zhen was responsible for her "death".
Zhu Cai Wen found a former servant of House Sung working as a cook in an inn in the northwest of the Forest of Chin. This person is probably working with the House of Gainful Protection to restore House Sung.