Who is Shillawn from Crystal Singer and what is their importance?

Shillawn and Killashandra first meet on the space shuttle. He asks a lot of questions about the crystal singers on the ship, and when Killashandra finds herself unable to avoid him, she claims that he is infringing on her privacy.

Shillawn is described as a kind but overbearing man, who loses his hearing during the symbiont fever, and thus, he is unable to become a crystal singer. He then becomes a researcher on Ballybran instead.