Hiki no Ama, the wet nurse who saved and raised Yoritomo: Why did the Hiki clan have to meet such a tragic end?

Hiki no Ama was played by Kusabue Mitsuko in the historical drama "The 13 Lords of the Kamakura." With her big smile when she met Yoritomo and her tolerance for him as if he were her own child, you might get the impression that she was a very kind grandmother. But was this actually the case in real life? As you know from the drama, she was right in the middle of the brutal power struggle in Kamakura, and she was not just a kind grandmother, but …