The relationship between David and Rosalind?

Rosalind Morton is David's cousin, close friend, and a member of the telepathic group. Their relationship evolves into a romantic one towards the end of the novel. She offers her insight to both David and Petra, and she is quite protective of them. As a cautious individual, she is also very loving and optimistic, and helps plan and make decisions in the best interest of David and Petra.