Lore

I realized that the symptoms those three children experienced was a curse on the settlers, a curse from god, a curse of death. - Complete the Passage

But this man had been able to cure his children. The slates specifically state that he saved his children, no one else.

TH, while reading the slates, mentions that someone else wrote some parts, these are most likely by Dian. Meaning someone else was there way before her and TH talks to Dian mentioning "our mother/father".