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It started with Wally, obviously. Bruce had even actively encouraged Dick to invite Wally over, wanting his ward to have friends he could relate to. Well, 'actively' is a relative term, but he basically just never said no, and at some point Dick just stopped asking and started assuming.
Somehow, the room next door to Dick's ended up in a perpetual half-cleaned state, with Flash paraphernalia and a few other superhero things mixed in, too. It didn't even occur to Bruce to look until one day, when Dick left for a study group with a Flash hoodie over his shoulder.
He opened the door, blinked, and turned and yelled, "Alfred!"
Alfred magically appeared down the hall, and Bruce said, "What is this?"
"I know it's a mess, sir, but the war against Master Wallace's natural entropy is proving quite daunting," Alfred said, leaning in to look at the underwear hanging from the bedpost and the comics and books scattered everywhere.
"No, I meant, since when does he have a room?" Bruce asked in bewilderment.
"Really, Master Bruce, one would almost think you unobservant. Master Wallace moved in about a year ago."
"Oh," he said. But it didn't really make much difference in the end, except to keep Dick happy, so he let it go.
The first time Kaldur came over, it was because he was bleeding out, and the Batcave was the nearest safe haven. Bruce stitched the boy up, and got him hooked up on IVs and a water-breathing tube of his own invention, designed to help Atlanteans survive on the surface.
He hadn't expected to need it so soon, but he was glad to see it worked. It wasn't strictly necessary in this case, but it should help, if only just a little.
They were all exhausted, and all of them were covered in blood, mostly Aqualad's. Bruce sent Dick upstairs to shower, with the promise he could return to check on his friend, who was holding steady. He made this promise with the silent conditional of if you're still awake, and met Alfred's eyes over Dick's head.
Bruce used the shower in the cave, and sat up for hours yet to monitor the boy, until Alfred came to relieve him for an hour or two.
The Batcave had a high-tech infirmary that most hospitals would be jealous of, but it was never built for long-term convalescence. Put simply, it was not a comfortable place to be. And although Kaldur'ahm was technically healed by Bat-standards, that is, walking and talking, he still wasn't able to stand for long periods of time.
Dick kept giving him the eyes, and Alfred kept handing out cutting little remarks about comfort and relative recovery time, and the poor lad, so Bruce finally just gave up and moved him to a room upstairs.
If it ended up being the one across the hall from Dick's, well, Bruce just said 'a room', and left it to them to sort out.
Dick could keep a secret to save his life, but that was about it. He was really bad about hiding things he didn't want to hide, and he didn't like keeping important information, like, say, his name from his team, who he trusted. So Bruce honestly knew it was only a matter of time.
So he wasn't as surprised as he could have been when he wandered into the kitchen one morning to find Superboy at the breakfast table.
He grunted an acknowledgment and shuffled right on past, heading for the cupboard.
"I told you this was a bad idea!" Superboy hissed, and Dick laughed. Bruce had his back to them, but he knew his ward well enough to know he was smiling.
"Nah, I told you, it's fine. He's just kind of a zombie until he has his coffee. It's nothing personal."
Bruce ignored this, because he could function perfectly fine without caffeine, thankyouverymuch. He could, really.
He sat down, and scowled at the piece of toast on his plate. Butter magically appeared from across the table, so he slathered some on the bread, opened the newspaper, and then took a bite of toast. He shoved his plate of bacon out in front of him, and it promptly disappeared, crunching sounds heralding the arrival of a sausage link beside his toast, as he and Dick automatically readjusted Alfred's balanced breakfasts to their personal tastes.
He could feel Superboy's—no, Conner's eyes on him, but he ignored it, sticking the sausage link in his mouth, picking up the newspaper and mug of coffee, and wandering away down the hall to get dressed.
"Told you so," Dick said behind him, and Sup—Conner asked, "Is he always like that?" and he dismissed the whole event, focused on the stock market's closing price from last night.
Conner wasn't there when he got home, but he came back, now and again. Dinner time when all four, or even three of the boys were in house soon became a localized disaster, but Dick smiled and laughed and climbed on Conner and bantered with Kaldur and threw peas at Wally, so he couldn't really bring himself to care that much.
Bruce didn't really notice M'gann as much as he noticed random plates of cookies and brownies and everything ranging from banana bread to Divinity left out where hungry teenage boys and wandering mentors would find it.
In fact, he didn't really think much about it, until he walked into the kitchen one afternoon to get a water bottle. He was messing with the programming of Robin's wrist-comm, and walked right back out.
Something was wrong. There had been movement when he'd walked in, and stillness when he'd walked out.
He leaned back through the doorway to see a floating bowl of chocolate batter and matching mixing spoon just hanging in the air. He quirked an eyebrow, and M'gann slowly wiped into being, head to toes, "Um," she said, and a lump of batter dropped from the spoon to the floor. "Oops, wait, I'll get that, silly me, I was just—"
Only she turned too fast, and a thin stream of batter was flung out, coating the walls and his face.
Megan made a sound like argleerk, and froze.
Bruce dragged his finger through the batter, then stuck it in his mouth.
"Needs vanilla," he said, and walked out.
As long as the kitchen was clean enough to make supper in, he didn't mind. On second thought, maybe they'd order pizza tonight, and he could relegate the teens to the TV room, and maybe have a little peace and quiet. Then he licked his finger again, and amended the list to 'peace and quiet and cake'.
And then he returned from patrol one night to find a boy jacking the front tires of the Batmobile.
It was a pretty forgone conclusion that he'd end up slung in the car and taken back home to be trained.
"Another one of your strays, Master Bruce?" Alfred asked, looking the boy up and down.
Jason waved jauntily at him, and Alfred returned the gesture with a proper little bow.
"Alfred, would you mind making up a room? Maybe the red one?" The red one had motion sensors installed, along with various other security measures, and was the most wired guest room in the house.
Alfred coughed. "Beg pardon, sir, but Master Roy currently occupies that room."
"Roy has a room here?"
"Yes, sir. He hasn't been in residence for a while, but the room remains ready for his no doubt eventual return."
Bruce blinked, but moved on. "Okay. The green one?"
"Miss Megan, I believe."
"The blue one?" he asked rather desperately.
"Master Kaldur'ahm, sir."
Bruce stared at him. "How did I not notice this? How many teenagers live at my house anyways?"
"All of them, sir," Alfred droned, in the way he always did while hiding a smile at Bruce's expense. "Might I suggest the white room near Master Dick's?"
"So, I'll have lots of brothers and sister?" Jason asked. "And they all do what you do?"
Bruce intelligently said, "Er," which was confirmation enough for Jason.
"Best day ever!" he cheered. "Thanks, Bruce," he added, throwing away just enough pride to give his new mentor's waist a quick squeeze, and he looked up and said, "You won't regret this, I promise!"
He thought it was probably a measure of how messed up his life had become that, when he reached into the dryer to get some socks and came up with a pair of girl's panties instead, his first thought was, oh, good, they gave Artemis a room. They've finally accepted her as team.
Then the lack of cloth and the color gave him pause, and he hurriedly dropped them back in the machine, wiping his hand on his shirt.
He felt his stomach sink as a horrible thought occurred to him. Surely Green Arrow had not let his sidekick out without giving her the talk, right? All the kids had had it, right?
Except Conner. And Dick, he knew that, and probably Miss Martian, too; cultural differences and all, but surely the rest...?
Maybe he could get Alfred to do it.
"Family love is messy, clinging, and of an annoying and repetitive pattern, like bad wallpaper."