Who is Lin from Perdido Street Station and what is their importance?

Lin is an insectiod artist. She creates her paintings by eating wild "color berries" of different hues and collecting her excrement for use as paint. Lin uses sign language to communicate with Isaac, while he speaks to her in English. Lin is a khepri, who has "bulging, mirrored eyes", which present a million tiny images that are connected by her brain into a coherent whole. She is hairless with "red, tight" skin. Isaac and Lin have been together for two years but have tried to keep their relationship a secret to avoid shame and public censure.