Sirius Black was in his final year of Hogwarts School of Witchcraft and Wizardry. He was however also late for class. It was already Friday but the class was one everyone in the class complained about because in their final year, the Slytherin and Gryffindor houses had been put in the same Defence Against the Dark Arts class. Their new professor had given them a class activity to see how much they had remembered from last year.

A pair had been first to go up, two Slytherins. The winner had to duel the next in line until they lost their duels –no exceptions and no matter how many duels they won, they had to fight the next until they lost. The longest had gone for Remus Lupin to fight four others, two Gryffindors and a Slytherin, before he lost to his fourth, James Potter. James had the pleasure of immediately duelling Lucius Malfoy, who after a few minutes of a battle had his wand disarmed. No sooner had James stopped smirking and cockily laughing at his opponents defeat than none other than Bellatrix Black was next.

She wore no expression on her face but James's smirk wore thin and turned to pure anger. He had come out of their fight with two black eyes and a broken nose. And he still remembered everything she had said to him on that train ride home at the end of their last school year, and therefore was determined to beat her. They bowed, and so the fight began. Flashes of coloured lights illuminated the classroom, which had been cleared out for the duelling.

There were a number left, and due to his tardiness, Sirius was forced to the back of the line. He wasn't the slightest bit worried about having to duel his cousin, James seemed to be wearing her out. But clearly he was wrong. After but a short few minutes, James getting more and more aggravated that he wasn't able to disarm her but Bellatrix hardly breaking a sweat as she blocked and threw spells with more and more power, James' wand flew out of his hand. He snarled at her as he moved away, sitting with everyone who had their turn.

Bellatrix pursed her glossed lips, standing and moving back once more. She tugged lightly at the back of her black school skirt as it had risen ever so slightly, and smoothed out her white shirt. The next duellist came on, and she had disarmed them in seconds. She was refraining from using any more magic than she was allowed, simple arming and disarming spells that were hardly any thought to her. By her fifth opponent, everyone was watching intently and Bellatrix was still hardly breaking a sweat. Sirius watched as his cousin's arm extended, her wrist giving the tiniest flick to produce an incredibly powerful disarming charm. At her seventh opponent, it came to Sirius's attention that everyone was watching her move with ease and were completely taken with how incredible she was –including their professor. He had moved forward slightly to get a better view, watching her disarm every spell with ease and create another with hardly a thought. His eyebrows were furrowed in concentration. He had never seen such a young witch duel so expertly. One of her duels took a while and as he looked at the line in front of him, Sirius began to realise he might duel his cousin after all as there were only two left in front of him.

After but a few minutes it was Sirius's turn. He walked in front of her as she flipped a lose strand of hair back that had fallen out of place at no doubt her many duels, and her tongue ran along her lower lip. They bowed as they always had to, though their eyes never left one another. Sirius was the first to make a move, his cousin blocked the spell immediately. She threw one back extremely quickly, almost catching him off guard had he not been watching her so carefully. They fought, their magic becoming more powerful, their spells clashing with one another hard, hitting each other's disarming spells. The classroom looked like a display of a thousand firecrackers going off at once. They were getting lost in the fight, they were enjoying it too much, though they didn't say a word to one another. Sirius threw a spell he had seen her use, and it caught Bellatrix off. She disarmed it quickly, but couldn't help but grin. Their fights always turned nasty and suddenly, as they both realised how nasty this fight was about to get they didn't care that there was 40 others watching, nothing would stop them.

Throwing a curse at her cousin, Bellatrix watched as Sirius's eyes widened for just a moment before blocking the spell.
Their professor shouted, "TO DISARM ONLY!"
They weren't listening. Sirius countered her curse, returning one twice as strong to her, which she blocked. Her retaliation was harsh throwing three spells at him at once, which he fought off a little harder this time. They fought harder, and harder until they were panting, as their curses had turned dangerous, the rest of the class were against the walls and their professor was too scared to intervene for fear of being hit with a curse.
Their fight was brutal and aggressive, and something they loved. Both were grinning and laughing at one another at the thrill of the fight and the memory of their many duels, their hearts hammering –though they didn't notice, Bellatrix used her curses wordlessly but Sirius continued to murmur his under his breath as he blocked his cousin's curses and threw back others, which she too blocked with ease.

Their professor was fed up, "BLACK! And ..BLACK! STOP!"
They heard him but hardly stopped.
"One second professor, my cousin is wearing, thin," Bellatrix said as she threw another curse at her cousin.
"You're not going to win!" Sirius laughed, throwing another curse at his cousin.
"Neither are you!" she spat back.
They knew they were going to be in trouble for this, but they couldn't care less. They were focussed on each other and nothing else.

A sudden final disarming charm from them both at the same time had their wands flying out of their hands. They stopped dead, Bellatrix's hair having been thrown forward somewhat and Sirius's shirt now more messed than it was before. They were both panting.
"A tie it is." Sirius murmured.
"Reduel!" a scruffy looking blonde haired Gryffindor yelled from the crowd that had been watching, everyone agreed loudly.
"Gladly." Both Bellatrix and Sirius said as they went for their wands.
"ENOUGH!" their professor yelled, stopping them both and looking extremely troubled, "Both of you get to the headmaster's office. And DETENTION for a WEEK! Everyone OUT! Class dismissed!"