Who is Richard Rigel from Lila: An Inquiry Into Morals and what is their importance?

Richard Rigel and Phaedrus meet in Oswego, but they don't really get to know each other until they arrive in Kingston. Rigel warns Phaedrus about Lila's mental condition, as he has known her since they were children. Rigel's character plays "devil's advocate" to Phaedrus's intellectual theorizing, and he sets Phaedrus's thoughts reeling when he counters his arguments with Victorian idealisms. In the end, we learn Lila is obsessed with Rigel.