Team Free Will, with the new members Gabriel and Jack, is the last group of people put into the war room. It's partially because Sam was stalling, but mostly because Dean just wanted to eat pizza. Sam never mentioned Lucifer, and no one seemed to notice he was so quiet as he was trying to find the opportunity to.
As promised, Lucifer is in the war room with the rest of the gang. Sam looks over at him, and, almost as if Lucifer can sense it, he looks up as well, just long enough to make eye contact. Sam can almost hear the message Lucifer is sending him — that this is his chance. It's now or never.
Sam makes a split second decision and stays with his brother.
Jo and Michael occasionally glance over at Lucifer, and it's obvious they're talking about him, but otherwise, he's mostly ignored for the first few minutes. He doesn't appear to mind, just casually leaning against the wall and looking at his hands, seeming bored.
"Hey, Sammy, yoo-hoo." Dean waves a hand in front of his face. "Anybody home?"
Sam snaps back into reality. "Yeah, sorry."
"You okay?" Dean asks, sounding concerned.
"I'm fine," Sam says. He glances over at Lucifer again, then says, "Hold that thought."
Sam walks over to the archangel, who doesn't look up until Sam says, "Hey, been a while."
Lucifer meets his gaze, a small smirk on his face. "Yeah, really. I have to admit, I wasn't expecting you to actually come talk to me."
"I wasn't gonna give you up that easy."
"I can't say I'm complaining," Lucifer says.
"I can," Sam says, earning a confused look. "Where'd K9 go? He was supposed to be my motivation to come talk to you."
Lucifer chuckles. "Not here. Dean would throw a fit if he saw him."
"Dean's gonna throw a fit anyway," Sam reminds him. "You might as well throw K9 in, too. Get it all over with at once."
Lucifer shrugs. "If you say so." He puts two fingers in his mouth and whistles, loudly enough that Sam is almost surprised he isn't deaf.
K9 runs into the room, his metal paws pitter-pattering on the concrete floor. He runs up to everyone, disappearing just as fast as he appeared. He doesn't acknowledge any of the surprised noises he earns from existing. Finally, he settles down next to Lucifer and Sam.
"What, no tennis ball?" Sam asks the dog teasingly.
"Should I get the tennis ball?" K9 asks.
"No, no, you're good," Lucifer tells him.
"I'm a good boy?" K9 says hopefully.
"You're the goodest boy," Sam replies. He looks over at Lucifer to point out, "He's acting much more doglike than he did earlier."
Lucifer shrugs. "I got bored, figured I'd rather hang with an actual dog than a person-dog, so I changed him a little bit."
"I thought you killed it," Dean says, looking at his brother accusingly.
"He did," Lucifer replies. "I brought him back. C'mon, Dean. I'm an archangel. It's not that hard."
"What's his name?" Charlie asks. "Or her name?"
"I'm K9," the dog tells her. "You may call me 'he,' 'she,' 'they,' or by my name."
"K9?" Charlie repeats, a sudden light in her eyes. "From ?"
"Inspired by," Lucifer replies. "It's not actually K9."
"Sweet Tardis of Gallifrey, I love him!" Charlie squeals. She runs over to him and crouches by the dog's side. "Hi, K9! I'm Charlie! Can I be your best friend?"
"Yes!" K9 replies excitedly. "I wanna be everyone's bestest friend!"
"Hard to believe he's your dog," Sam jokes, looking over at Lucifer.
"I know, right? I'm beginning to think I should have named him after Jack," Lucifer replies. Seems like that would fit him well.
"Since when are you two friends?" Charlie asks, looking between the two of them as she stands up, keeping a hand on top of K9's metal head.
"For a while now," Sam replies. He looks specifically at Gabriel as he adds, "We finally gave up on hiding it. If someone doesn't like it, that's their problem." He looks over at Dean, almost nervously, not sure what to expect from him. Surprisingly, instead of looking upset, he just looks confused.
"So you and Lucifer, you're..."
"Friends," Lucifer substitutes. "The word you're looking for is friends, not that you'd know that, cuz you don't have any."
Dean glares at him for a moment, then looks to his brother. "Okay, I was just going to assume you knew him better than me, and maybe, just he's not actually a grade-A douche, but I'm gonna assume that's not the case, so what's the deal, Sam? Out of anyone here, you just to pick Lucifer? After everything he's done? Something's not adding up here."
"Maybe it doesn't have to add up to you," Sam says. "It's my life, Dean. I think I can pick my friends without your input."
"So did I, but apparently not!"
"Just, little thing," Gabriel says, interrupting them. "You're two are standing awfully close for "
Sam sends him a glare, and he just shrugs.
Dean rolls his eyes. "Shut up, Gabriel. Go be jealous on your own time."
Sam was originally going to deny it, but just because Dean seems to think it's so impossible, Sam wants to prove him wrong. He puts his arms around Lucifer and presses their lips together. He thinks he hears a soft laugh from the archangel, who doesn't hesitate to kiss him back. Sam almost doesn't want to stop, but he knows they can finish this later. Right now, he has a fight to end.
"Sam, what the hell?" Dean yells.
"I'm done keeping secrets, and I'm done living by your rules," Sam says. "Everything's out in the open now, okay? I'm dating Lucifer. I have been for weeks. Nothing you say is going to change that, so don't even try."
"Sam, this is ridiculous! Why would you ever choose Lucifer? There are literally zero redeeming qualities in the guy! At least with Gabriel, yeah, he's a serial killer, but he has a sense of humor, which is way more than I can say for Lucifer." Realization shows on his face as he seems to figure something out. "This is your idea of a rebound, isn't it? You left Gabriel, then Jess disappeared, and now you're on to Lucifer. You know that's not a healthy base for a relationship, right? I mean, it's a thing that people do, yeah, but it never ends well. You have to know what's coming."
"Yeah, you know what, it because of Gabriel and Jess, but it's not a rebound. Because after Jess disappeared, Gabriel wouldn't let me near him, and I couldn't talk to you and Cas."
"You didn't want to talk about her," Dean says defensively. "That's not my fault."
"No, I didn't — not at first. And when I told you that, you just let me tag along and listen to you two talk and basically ignore me. But Lucifer was there. He was willing to talk about Jess, and he was willing to sit on the roof and say nothing for hours just to keep me company. He was always there if I needed someone."
"Of course he was!" Dean snaps. "Because he's an asshole and no one else was willing to talk to him!"
"You know what? That's exactly what I thought, too. But he's actually not."
"I mean, I kinda am," Lucifer says.
Sam elbows him in the ribs, more for show than to actually hurt him, because, as he learned the hard way that morning, he would be hurting himself much more than he was hurting Lucifer.
"Maybe he an asshole to you, but you're just as much of one back," Sam says. "Everyone is. Has it ever occurred to you that maybe the reason he doesn't like you is because you don't like him?"
"Just, for the record," Lucifer says, "that's not entirely true. You're just kinda annoying, and you make it really easy to make fun of you."
"Okay, Lucifer, not helping."
"When do I ever help?"
Sam groans in frustration. "Dammit, Lucifer, will you just cooperate for ?"
"Oh, yeah, what a nice, healthy relationship," Dean says sarcastically.
"Why do you care, anyway?" Charlie asks. "It's Sam's life."
"But it's not just Sam's life!" Dean snaps. "Once Chuck lets us out of here, it'll put life in danger! That's what he does! He uses people and he hurts people and he doesn't care!"
"I don't know, man," Charlie says. "He's been pretty nice to me since I got here."
"You don't even know him, Charlie. You don't know everything he's done. Hell, you don't know he's done."
"I do too!" she protests. "I've read the books!"
"But you weren't there! It's different looking at something through pages in a book or a tv screen and actually experiencing every single moment of it! And, honestly, you should be able to figure out how much of a douche he is just from the books!"
"Enough with pick-on-Lucifer day!" Jo says.
"Isn't every day pick-on-Lucifer day for you?" Meg asks.
From here, Sam completely loses track of where this conversation is going. Jo and Meg start a side argument, while Dean continues fighting with Charlie, until finally, Michael yells, "Everybody shut up!"
Instantly, everybody in the room lapses into silence. For an ordinarily quiet guy, he can be intimidating when he wants to.
"Sam's love life is none of anyone's business except for his," Michael says. "What's that thing you humans always say? 'If you don't have anything nice to say, don't say anything at all?'"
"Then I guess I won't be talking to Sam until they break up," Dean says.
"Then don't talk to Sam," Michael says. "Everybody just stop fighting, or I will lock you all in different rooms for a week, and solitary confinement can lead to insanity real quick in humans. Trust me, you don't want me to do that. Are we clear?"
Everyone just nods. It doesn't sound like something he'd do, but this doesn't sound like him, and no one is willing to test the new Michael.