He even has his own set of Ten Commandments.

When she set out to create a show about a girl who talks to God, Joan of Arcadia creator Barbara Hall wrote up some rules - including "God cannot directly intervene" and "good and evil exist" - to give writers and staff a framework for the world they were crafting.

Going into the second season beginning Friday (8 p.m., Channels 12, 7), "We still have to be vigilant," Hall says. "Even now, we find ourselves asking, 'Can God do this?' "

Having God appear to 21-year-old Amber Tamblyn's Joan in several different forms was a way of bridging another obstacle for the series, which is up for three Emmys Sunday.

"One of the problems everybody has with God is we think of Him as a human personality," Hall says. "Even if we had someone say 'I don't really look like this, I'm just moving around in this body' you're still creating an image in people's head that is consistent and concrete."

Charged with playing a part that is intended to be specific yet unique, some of the actors who play Joan of Arcadia"s God have also created commandments of sorts for the role.

"I think of it as a grandmother sort of 'OK, Joan, here's the voice of experience,'" says Kathryn Joosten, who has played God in several episodes. "It's very easy to keep it consistent because I didn't try to do anything different than just me. God is a little more wary and perhaps not as energetic as I would be personally, but she's got a lot on her plate. She's seen it all, done it all, been there, done that."

Joosten doesn't often get recognized in real life for her role as God. She's much more likely to be identified as her dearly departed character Dolores Landingham from The West Wing - even on the set of Joan, where the character was referred to as "Mrs. Landingham God" in one early script.

"Keep it simple" was the advice given to Juliette Goglia, who plays the bespectacled "Little Girl God."

"It's a very intelligent part," she says. "They told me just keep it simple with Joan and tell her the truth and to have faith in God and stuff."

On the other hand, Kris Lemche often gets recognized as Joan's "Cute Guy God." "I've actually gotten used to hearing someone call out 'God' and then turning around, which is really bizarre," he says.

God will have darker and edgier material to play this year, as Joan deals with a crisis of faith. In last season's finale, Joan was diagnosed with Lyme disease and convinced that her interactions with the deity were "hallucinations" brought on by her illness.

"(Joan and God) have an entirely different relationship this year," Hall says. "... Joan is evolving as a person. Her relationship with God will evolve as she does."