The Only It's Always Sunny Characters To Appear In Every Episode
If there's one thing the five classless, clueless, bar-running bullies of the Its Always Sunny in Philadelphia gang have in common, it's that they all hate each other nearly as much as they hate themselves. This is evidenced by that fact that their only source of camaraderie appears to be gossiping about whichever member is out of the room at any given moment. Unfortunately for them, they're all so endlessly despicable that they couldn't find other friends to hang out with if they tried.
That's great news for us because it means we can reliably tune in to each new episode of what's about to be the longest-running live action sitcom in history and find them at Paddy's Pub in South Philly, hard at something other than work. But as great a tight knit comedic unit as Dennis, Dee, Frank, Mac, and Charlie are — not to mention their friends (or rather, lifelong enemies who always wind up in their line of fire) — only three of them have appeared in each episode of this long-running show.
Dee Reynolds didn't last long as the voice of reason
When we first met Dee Reynolds, she was the voice of reason. It didn't last, thankfully, largely because Katilin Olson's gigantic comedic talents would've been wasted if all Dee did was wag her finger at her brother and his idiot friends.
So the showrunners turned her into an equal and gleeful participant in the Gang's hilarious depravity. She destroyed the life of a priest by pretending to fall in love with him and tricking him into leaving the clergy, frequently exploited and antagonized the Waitress (often causing her to relapse into alcoholism), and tried to rope people into a scam after falling for it herself. Oh yeah, she also invaded a house to steal a priceless vase, held a funeral for a fake baby while cheating the IRS, and got addicted to crack during a welfare scam that she ran with her brother. She wasn't always alone in these schemes, but she didn't exactly have to be pushed into them, either.
Sometimes you pity Dee for always being the butt of the joke, having her car destroyed by the other members of the Gang for the umpteenth time, or being hopelessly deluded about her abilities as an actress or comic. But then she turns around and does something terrible, and you realize she deserves every hilarious punishment she gets. Luckily for us, every single episode of It's Always Sunny has involved Dee's schemes and, usually, her comeuppance.
Ronald 'Mac' McDonald is hopelessly deluded
All due disrespect to Dee Reynolds, who believes she's one lucky break away from Hollywood superstardom despite lacking any discernible talent, but the award for "Most Deluded Employee at Paddy's" has to go to Mac (Rob McElhenney). The constantly body weight-shifting, recently openly gay co-manager of Paddy's Pub truly believes he's an intimidating badass despite never having won a fight and being generally clueless about nearly everything.
Luckily, not a single episode of the show has deprived us of his cringeworthy, hysterical antics or people's exasperated reactions to him. He can usually be found doing air karate (almost always coupled with wish whoosh sound effects) or giving worthless "ocular pat-downs" to the pub's few visitors. Well, that's when he's not daydreaming about beating up ninjas or muggers, preaching to others about a God he makes no effort to follow or emulate, writing unreciprocated love letters to Philly sports heroes, engaging in harebrained schemes that go nowhere, and, of course, getting absolutely blasted with his buddies at the bar, using booze they likely would've sold to customers ... if they had any.
Charlie Kelly is a nice guy in a bad crowd
Perhaps the one genuinely good human in this group of selfish sociopaths is janitor Charlie Kelly (Charlie Day). That's not to say he's innocent. He participates in their schemes, huffs paint, lives in squalor with Frank, and stalks the Waitress despite her repeated demands that he leave her alone.
But unlike the other members in the Gang, he doesn't appear to understand that his behavior is unacceptable. He thinks the Waitress is just playing hard to get and that he's helping her by following her around and making unauthorized entrances into, and repairs in, her apartment. Above all, he wants to make others happy, eat his cat food in peace, and do his so-called "Charlie work" well (which is usually fighting rats with clubs or intentionally causing lethal carbon monoxide levels to accumulate in the basement, hoping to drive the rodents away). It's probably fair to say that if he hadn't gotten involved with such a disreputable crowd, he would've turned out much better.
But he did, so he didn't, and our sitcom diet is a whole lot richer because of it. Charlie Kelly might be functionally illiterate, but he hasn't missed a day of work on It's Always Sunny since its 2005 debut.