You think there’s no upside to multiple-personality disorder? Check out Stephanie Diaz in Lookingglass Theatre’s dizzying The Great Fire (now extended through December 4). True, most of the actors play more than one role, but Diaz’s seven include three big ones in a broad range: a widowed Polish mother of five, the wealthy Mrs. Tree, and a male archivist who, in this re-imagined production of John Musial’s 1999 original, also stages a high-spirited puppet show.

Diaz’s favorite? The archivist. “John sent me a new version of the script,” says Diaz, 37. “And he wrote, ‘The archivist has been added to your track. I hope you will find it amusing.’ And when I read it, I cried—with gratitude! I thought, ‘I can’t believe I get to do this. I get to play an old dude, and then do a puppet show!’”

Originally from California, Diaz trained as a puppeteer in Seattle, where she specialized in bunraku puppetry.

But when Musial wanted her to build the puppets, one being Marquette and the other Joliet, “I thought of saying no,” she says, “because I’d never built hand puppets. I was going to have to sculpt faces.” But friends told her to “man up,” and after buying two papier-mache skulls from Michael’s (“That’s not cheating!” her puppetry teacher told her), she “just started slapping papier-mache pulp on them, and they became what they were.”

“The characters came after I made the puppets,” she says. “And when they were done, they came out so funny. I tried to make the priest kind of fat, but he didn’t come out fat—he came out sweet and hapless, and I gave him a gin-blossom nose, but nobody picks up on that. I tried to make Joliet look like a dick, an a**hole.”

Copying the puppet Marquette’s slightly superior, quizzical look, Diaz tells me she had to give him a “fluty, hooty voice.” For her, the key to any character is finding the voice. 

Talking to me, she drops effortlessly into the West Indian accent of the cabbie who brought her from Midway to Andersonville when she first moved to Chicago in 2004. Little old ladies wait for her after The Great Fire, she says, to congratulate her on her Polish. For Mrs. Tree, dialect coach Eva Breneman helped her decide on something “in the neighborhood of Katharine Hepburn.” (“The Katharine Hepburn sort of thing, don’t you know…” Diaz says in an upper-crust drawl.) The archivist, she says, is a blend of her dad—who reportedly sounds like Bill Clinton—and Christopher Lloyd in Back to the Future. (Musial suggested Lloyd after noting that the archivist was starting to feel “a touch Mr. Rogers.”)

Diaz is a huge fan of Lookingglass, who remind her of the Muppets. “If you watch them do a song,” she says, “the ones in the background are always doing something—something funny or specific or cute. So if somebody happens to be looking at me, I want it to be interesting. I want all parts of the canvas filled in. And Lookingglass shows do that.”

Diaz calls performing in this play “a dream come true.” When she found out she’d gotten in, she was so excited she started screaming to her husband, “I got it, I got The Great Fire!!!” she says. “And my neighbors upstairs heard me scream ‘Fire!’ and came running downstairs….”

Next up for her is the “awesome” Accidental Rapture, at 16th Street Theater in January. Penned by Eric Pfeffinger and last seen in Chicago in 2003, it brings together old friends—two of whom have become hardcore Christians. Diaz describes her character as “one of the not-saved. She’s like a punk bike-messenger actress. She’s the white elephant in the room because she’s so out-there.”

Though Diaz says she could never be a director, she’s done some writing and in fact recently applied for a Hedgebrook residency to work on a novel. “But a playwright,” she says, “I am not. I’ve tried my hand at it, and it’s so hard.”

“I tried doing other things” besides acting, she says, “and I can’t. I was very unhappy. I like to be in plays.”