little Bill, and Charlie Weasley tag along with their dad to Order headquarters so Molly has one less kid to worry about that day
Arthur just needs to meet with Dumbledore really quick about something "you boys wait out here. Look after your brother Bill, I'll be back in a moment"
Bill takes his responsibility very serious and keeps a close eye on six year old Charlie (who couldn't be more content to chill on the floor playing with the rubber duck his dad gave him)
The door to the room they're waiting in opens and in walks Sirius Black.
He had long hair, painted nails, rugged muggle clothes and tattoos.
Bill has never seen anyone like him before, but he knew one thing; He was cool.
Sirius realizes someone is already talking with Dumbledore and waits, finally registering that he's not alone in the room, he smiles at Bill
"You're Arthur's sons, right? I'm Sirius Black"
"Yeah, I'm William and this is Charlie, he's six"
"I bet you look after him, don't you?"
Bill puffs out his tiny chest and nods. "I'm the oldest so I look after all my little brothers"
There's a pause and then Bill says shyly that Sirius' hair is cool
Sirius smiles, sits with the two boys for a bit and shows them all his different tattoos until Arthur is finished
Just as they're about to leave, Sirius pauses in the door to Dumbledore's office and casually salutes Bill "I'll see you around, Bill"
That night Bill asks his mom and dad for the first time if he could be called "Bill" instead of "William"
He starts asking to tag along with his dad to Order headquarters as much as possible but it isn't until a year later that he crosses paths with Sirius again
His hair is short now and Bill asks if he didn't like it long
"I do like it long, but sometimes accidents happen and you end up with an unexpected cut. I still look pretty cool, though, right?"
Yes he does. But Bill thinks the long hair was cooler.
Fast forward a couple years and his dad sits him down to explain that some bad things happened and Sirius is in Azkaban now
Bill is crushed, firmly in denial that Sirius is guilty (but the testimony of an 11 yr old who looked up to him doesn't mean much)
Throughout his years at Hogwarts, Bill grows his hair out, experiments with "cool" muggle clothes and secretly gets his first tattoo in sixth year
His mom hates it but he doesn't care
Then years later the second Order is formed and he finds himself walking into the new headquarters as a member
He steps into a room and pauses, staring at the person sitting by the fireplace.
Sirius looks up, and after a moment he smiles broadly
