In Nightfall, when Marella showed up, Fintan said, and I quote, "And I get to meet the new recruit-a Redek, no less. I'm assuming your mother doesn't know about this new hobby, given how much she sacrificed to keep you away."

I think it means that Marella's mom found out about the Neverseen somehow and when Marella was born, she was a target. She sacrificed her emotional sanity to keep her safe.

Personally, I think that Marella's dad is in the Neverseen or Marella's mom had a past with one of them.