Work Text:
Captain Marvel and King Phantom were both entities that might be considered good natured but were powerful to end the world itself in their own right if they so desired. Not that anyone would ever think they would do so.
Still, both of them weren't exactly people the Justice League wanted to get on the bad side of. Surprisingly enough, though, the two of them had no problem whatsoever to ruffle each other's feathers. Which caused a lot of undue stress to the Leaguers.
They'd found out that the two of them even knew each other purely by chance. They weren't on duty at the same time a lot, especially not since Phantom worked as a consultant to the Justice League Dark and the Captain worked with the Justice League International. But at one point in time they had both been at the same meeting and they'd just let it slip that they knew each other very well.
"When you have been around for as long as we have, it's inevitable to meet each other at least once. It just so happens that we have had a fair few instances in which we crossed paths."
They didn't give any other explanation than what the Captain had said then, words very obviously carefully chosen and filled to the brim with hidden secrets. And it was true, after all: Both of them were ancient.
No matter how far into the past you looked, you'd find another, even older mention of King Phantom. Thought seeing the child show up in one of the photos of the Wright brothers half transparent with a mischievous grin proved that he was older than all of them? Well, how about this mention of him in a text written in Salem during the witch trials? Oh, or this painting from the Ming dynasty that clearly portrayed him? Thought that was it? Well, no. Because, you see, there's this nice medieval song some royal had had written with his name in its lyrics. Or that vase with what was probably him from ancient Rome. Or this morsel they couldn't even place… Not to mention that there were some indications he might have actually witnessed dinosaurs.
They all also knew that the High King only preferred the form of a human child. Which they were thankful for, mind you. His true form, or really all of his less humanoid forms were… startling to witness.
As for the Captain, well… They knew that around 1100 BC, Shazam became a high priest to the pharaoh Tut III of Egypt. So while he, too, refused to put a certain number on his age, claiming that it was too complicated to keep score of it, that meant that he was at the very least well over three thousand years old, too.
Now, all of this checked out and all of that was fine in itself. The problem wasn't there.
The problem was that no one could actually figure out whether the two of them liked, tolerated or hated each other. Were they old Acquaintances? The answer they would give was "Something like that.". Old friends? Again, the old comment had been "Something like that.". Enemies, foes? All they acknowledged this one with, as well, was "Something like that.".
There'd been other things they'd asked, something more concrete. The information here was just so self-contradictory, though.
Holding a grudge against each other? "Oh, definitely" according to Phantom.
Used to working together? "Hm, sure, you could call it that…" in the Captain's words.
Uncaring about what the other one did in their time? "Why wouldn't I be?" and "Obviously?"
Trusting each other? "That depends…" On what? Well, that hadn't been dinged with any other response than a laugh in passing.
Annoyed by the other's presence? That one never got a straight answer, they just used that question to call each other out on petty things every time.
Happy to see each other again? "Meh"
Bothered by being reunited? "Well. It's not something I'd say I didn't care about."
Interested in each other's opinions? "He's wrong. I don't care whatever he said to you, he's wrong and I'm not going to change my approach just because he- Wait. Did you mean in general or was there something specific he said?"
Allowing each other to breath into their respective domain? "I would rather die! …Again. I'd rather die again… You know what I mean!" or "…Have you seen him fight? He just throws his powers aground like- No! He can't- Magic is a lot more complicated than his little ecto-sauce-shows!"
And every other question they'd come up with had been equally unhelpful to figure out what they were to each other. Apart from appalled at the thought of accepting each other's advice and trusting the other's expertise.
In the end, John Constantine had helped them make a decision on how to handle their strange relationship with each other. "You shouldn't bloody care, ya twats. Bit of dimwits, you lot, eh? Keep 'em from fighting and you're good. 'S all that matters, really. 'Cause, see, those two getting in a serious fight? Bloody Champ of Magic and Ruler of everything in the Beyond? 'd make hell look like a damn nice vacation. And I'm not gett'n roped in on that. Savvy? Great. Now, pass the bloody bottle back over 'ere," had been his exact thoughts on the matter.
After getting that very helpful and not at all concerning opinion from the man who'd called a god pathetic once, the Justice League had decided to not let them be in the same room again, except for world ending crisis type of situations. Judging by Constantine's grunt, he approved of the decision.
The truth of the matter was this, though: Danny Fenton and Billy Batson knew each other and spend a lot of time around each other.
They had both been semi-adopted by John somewhere between "shit, that's an actual child" and "you're parents are bloody what?!". Both of them had gotten some form of protection and tutelage from the mage after that. So it'd only been a matter of time before they'd met in the house of mysteries. And soon after, they'd found out about each other's secret identities, too. And about the truth behind their "ancient age".
They'd started getting along just fine. As it turned out, they had a lot in common besides being "ancient" child heroes. And so they had moved in together when they had ended up at the same uni.
Billy Batson and Danny Fenton were semi-brothers and roommates. And as any semi-brothers should, they semi-hated each other and also semi-loved each other.
In fact, the truth of that vague answer had been that Billy'd simply panicked after Danny had forgotten to hide how well they knew each other. The truth of the matter was that they'd thought the Leaguers' reaction was funny and thus intentionally kept it vague, even had a bet going to see who could confused them more.
The truth was that, ever since the League had found out that they knew each other, they'd started to make up "embarrassing" stories about each other and even threatened each other at home with coming up with an even worse rumour to spread.
"Danny, put you socks away, you absolute heathen, or I fucking swear I'll… I'll tell the entire League you started a cult as a joke and ended up needing me to save you because they wanted to sacrifice you to yourself!"
"You better didn't eat the last of my cornflakes again, Batson, or there will soon be rumours about that time Captain Marvel sleep-casted himself into a frog…"
"Do you want me to tell them how you accidentally froze the Library of Alexandria and portaled back in time to undo that?"
"Go ahead! I'll fucking tell them it was because you cursed all the books to be written backwards and I panicked…"
"Over one slice of pizza?! You wouldn't!"
"Try me."
And the truth was especially that John Constantine was not equipped™️ to break up a semi-sibling fight. Not at all. Hence: Vague threats to the Justice League so they'd deal with it.
You see, the truth was that Danny Fenton and Billy Batson had the time of their (half-)lives at the expense of the Justice League's nerves using High King Phantom and Champion of Magic Shazam. But, hey, being a child hero had to be good for something, right? Right.
And they didn't intend to stop any time soon, that much was certain.