I don't own anything because everything belongs to the wonderfully talented J.K. Rowling.
Sirius Black stepped out of his bedroom. His eyes darted around his house, reminiscing about how time were before, during, and after Hogwarts. His heart contracted painfully in his chest as he thought about his dead best friend. He so desperately wished to fix time and make sure that Pettigrew and Voldemort died before. A torrent of memories flooded his brain. Memories of him walking down the Hogwarts halls, pranking people. Memories of a mostly care-free life. Then came the memories of Azkaban and his friends being murdered. The dark, eerie, silent halls with dementors floating around every cell. A bitter, glacial wind blew, chilling his body down to the bone. Every brain cell of his screamed to run, to escape, to catch the despicable rat, and look after Harry. Sirius remembered the feeling of jollity when Harry declared that he wanted to move in. That moment was so short lived. He felt as if he should have done better. Better to protect his friends. Done better to protect his Godson. Suddenly Dumbledore's panicked voice rang through the hallway.
"Sirius, go to Ministry of Magic very quickly-"
Sirius barely finished hearing the rest of the sentence before he dashed out the door, nearly forgetting his wand.
As soon as he arrived, his eyes immediately started scrutinizing the area looking for a mop of messy black hair. He ran around frantically, shouting Harry's name, before spotting a group of kids duelling Death Eaters. Without thinking, he jumped into the scene and started disarming, jinxing, and cursing his enemies. He glanced at Harry, who reminded him so much of his dead best friend. Without thinking, he bellowed, "Nice one, James!" A disgusting, foul, and gut-wrenching sound made Sirius turn around on his heels, recognizing the voice that made his bones crawl.
"Hello Cousin. Long time no see, right?" Bellatrix taunted her cousin.
Sirius just fired a curse her way, which turned into a heated duel. Sirius soon felt himself floating, feeling emptied of emotion except for a grin that remained plastered on his face. The only thing he could decipher were agonizing, grief filled screams echoing through the halls.