Who are the Community Team (sometimes referred to as the Community Managers or CMs), and what is their role?
What is their relationship to the "Community" user?
They help you out. No, really. But yeah, that's about the most generic non-answer ever.
They review proposed sites passing through Area 51, revising, raising concerns, closing, destroying, and preparing for their launch as the situation warrants.
They moderate brand new sites as they launch, answer questions and attempt to communicate lessons learned on past sites. They appoint the Pro Tem mods, and hand the site off to them.
They're the navel of the SE administrators, always available for gazing.
They watch the various and sundry meta sites, answer questions, address or escalate requests and provide guidance in the use of the site's tools.
They occasionally answer emails.
They review moderator actions, offer advice, resolve disputes.
Now and then, they sleep. One eye open. Like birds.