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

Carrik is a crystal singer. He and Killashandra meet while he is on vacation. During their time together, Carrik tells Killashandra about the Heptite Guild and what it is like to be a crystal singer. Killashandra is so impressed with the Heptite Guild that she convinces Carrik to being her back to Ballybran with him. Sadly, Carrik is fatally injured in the shuttle explosion.