They live behind enemy lines, in places like Fells Point, Federal Hill and Canton - otherwise ordinary people with ordinary jobs and ordinary allegiances.
Until Game Day. That's when they put on their Sunday best - a football cap here, a jersey there - and head for the local sports bars to watch their charges and flaunt their true colors. Paint them burgundy and gold, not purple and black.
They are Redskins fans in Ravens country.
Tonight, their worlds collide as Washington hosts Baltimore at FedEx Field in Landover. It's an occasional showdown. Competing in different divisions of the NFL, the Ravens and Redskins meet every four years.
Not so their followers. Week after week, Baltimoreans like Josh Upton, Aaron Harris and Charles Penny - D.C. diehards all - rub shoulders with Ravens fans at pubs within earshot of M&T Bank Stadium.
But the ribbing, the jostling and the trash talk could be worse tonight.
"For me, it's the biggest game all year," said Upton, 24, of Glen Burnie. "It's bigger than [the rivalry between] the 'Skins and Dallas, because all of my friends are Ravens fans.
"I'd love to see us whomp the Ravens."
Upton said this last Sunday over a drink at a Federal Hill bar, one of several Baltimore sites where Redskins enthusiasts gather.
Years ago, most football fans in Baltimore rooted for the Colts. But the team was uprooted to Indianapolis in March 1984, leaving fans to make do for the next 12 seasons.
Meanwhile, down the road, the Redskins were a storied franchise, having won Super Bowls after the 1982, 1987 and 1991 seasons.
Baltimore got an NFL team back when the Browns moved to the city and began playing as the Ravens in 1996.
When the team won the Super Bowl after the 2000 regular season, fans draped themselves in purple and put flags on their cars.
Why do people lavish so much devotion on their teams?
"Being a fan is an ongoing escape - both positive and negative - from daily life," said Paul Swangard, managing director of the Warsaw Sports Marketing Center at the University of Oregon.
The level of devotion, or avidity, is often forged early and connected to something they hold dear.
"That might be family or hometown or an experience that has created this connection to a team," he said. "It's part of their heritage, and something they want to continue to support."
Hence the loyalty exhibited by fans like Orion Flaherty, 28, who was wearing a Redskins jersey and watching the game at Looney's in Canton.
"I watched Joe Gibbs growing up, and it's great to have him back," said Flaherty, referring to the coach's return to the Redskins after leaving football. He moved to Baltimore from Richmond, Va., a year ago.
Similarly, at Ryleigh's Brew Pub in South Baltimore, Aaron Harris was whooping it up for Washington, where he once lived.
"Gotta support the `home' team," said Harris, 28, who now lives in Pigtown. He takes pride in the fact that he lives "about 20 yards from the Ravens' stadium" but supports a club about 40 miles away.
Why, just two weeks ago, he sauntered into Ryleigh's wearing a LaVar Arrington jersey and lived to tell about it.
"There's not much razzing here," said Harris. That's because one of Ryleigh's owners, Tom Strawser, is a Redskins fan. Generally, the factions manage OK, though tempers do flare.
"The first Sunday this year, after we won and the Ravens lost, a Ravens fan saw me wearing my Redskins jersey and got in my face," said Strawser. "It was late, and he was annihilated [drunk]."
Strawser managed to calm him. "I said, `Gosh, it's not that important. Relax, it's only football.'"
The incident taught him a lesson, said Strawser: "You don't wear your 'Skins jersey in this town after 10 o'clock."
Tonight is an exception.
"I'd rather the Redskins beat the Ravens than anyone, because of what I have to hear every day," said Strawser, 32. "Every time the 'Skins stumble, people come in here and make it known that Joe Gibbs isn't the Second Coming."
A victory tonight would silence them. "I'd have bragging rights for four years," said Strawser, of Bel Air.
At another Federal Hill watering hole last week, a Redskins booster watched his team slip to 1-3 amid the jibes of some Ravens fans. For Charles Penny, a displaced Washingtonian who lives in Canton, the hoots are nothing new.
"Ravens fans hate Redskins fans more than vice-versa, and I don't know why," said Penny, 25, as he sipped a beer at the Mad River Bar and Grill.
"My roommates are big Ravens fans, and all they've done is talk trash to me about this game."
Worse, said Penny, is having to come home after work to a purple palace.
"Our living room is, like, a shrine to the Ravens. There are ... bobbleheads all over the place," he said. "Everything is Ravens, Ravens, Ravens."
A couple of seats over, Sean Jefferson sympathized.
"Working here in Baltimore, all I hear all week is `Ravens this' and `Ravens that,'" said Jefferson, 25.
He and other Redskins fans also must put up with no local broadcasts on most Sundays when the Ravens play at home. They must migrate to places that get a signal.
"I was born a 'Skins fan," said Jefferson, who moved here from D.C. several years ago. "I don't mind showing my jersey off in a Ravens bar. And when we beat them [tonight], well, I'll do all the trash talkin'."
Sun staff writer Mary Beth Kozak contributed to this article.