Who is Merit and Thoth from Sinuhe the Egyptian: A Novel and what is their importance?

Merit is a barmaid at the Crocodile's Inn, which is located in Thebes. She vs an older woman, but she is also very beautiful. Over the course of the story, Sinuhe becomes romantically involved with Merit. He even repeatedly asks her to marry him..... Merit refuses.

After Sinuhe returns from several years away from Thebes, Merit introduces Sinuhe to her godson, Thoth. It isn't until both Merit and Thoth are violently killed that he learns Thoth was actually his son.