Disclaimer: I got this idea from #Uncle Skull on AO3 and decided to write out my own take on it because... I CAN! Plus, I need more Skull in my life. You do not need to know anything about Katekyo Hitman Reborn to enjoy... but if you do know the anime and can link Skull with Phoenix it'll be a little funnier.
1. ) Upset at the 1957 Sorting!
It wasn't well known, but there were three Black Brothers, just as there were three Black Sisters. The third – or would it be the first? – was never recorded on the tapestry as he was born to a gypsy woman and a young Orion Black in 1946 from a one-night stand. It was a great shock when Phoenix Black showed up at Hogwarts in 1957 with an unrepentant smirk on his face as he came to the front of the hall with a confident stride. "You... Black... ?" a Slytherin girl sputtered, pointing at him. Phoenix snickered at her gaping face.
"Well, my mama did always say she could charm a wizard into her tent," he remarked flippantly. The Hat slipped down over his eyes and an old, amused voice echoed in his mind.
"Quite the unusual Black you are," it said. Phoenix shrugged.
"I don't like being put into a box," he stated bluntly. The Hat seemed to nod.
"Yes, I can see that. You are far too much of a free spirit to be placed into Slytherin. No... your fierce loyalty and earnest nature shall have you be a Hufflepuff!" Phoenix grinned as he swept the Hat from his head and swaggered over to the stunned table decked out in black and yellow.
"Yes, I am the first Black to be Sorted into Hufflepuff. Deal with it, Pureblood hacks!" he bellowed when he realized the whole Hall had frozen and the Muggleborns were looking around in confusion. There was a muffled thump as Professor McChullen face planted onto the table. Professor Slughorn gave a nervous laugh when the Head of Hufflepuff began to shake. Professor McGonagall moaned as a muted roar began at the Slytherin table. A moment later and Professor McChullen threw back his head in uproarious laughter.
"I like this kid!" he laughed. Unfortunately for the Professors, and whomever had the misfortune of royally ticking the bastard Black off, Peeves liked Phoenix as well – but that wouldn't be revealed for at least three weeks. For the time being, Phoenix was a 'normal' Hufflepuff Firstie who was having a grand time getting to know his year mates while various Slytherins were furiously writing a letters to their families asking if they had any knowledge of a Phoenix being born into the Black family and if not, could they please get to figuring out what the heck happened? Of course, as proper Purebloods, their language was... different but the core of the message remained the same. Professor McChullen was just pleased that he'd be able to show that Hufflepuffs are just as crazy as the other three houses before his retirement. Hopefully Sprout would be able to learn from these seven years~!