I'm blown away at the reception the last chapter got! Thank you to every reviewer especially, seeing those always brightens up my day. It also seems that the reveal managed to surprise a decent number of you which I'm thrilled at! Sirius is a great character, brilliantly expanded upon in many fanfics I've read and so when this story was being conceived he was always my choice for the Father of my OC. Because of this new connection things will also be different going forwards…

This chapter has some borrowed dialogue from Harry Potter and the Order of the Phoenix: Chapter 23 – Christmas on the Closed Ward.

"Leo…" Mary had said after an uncomfortable silence of both Leo and Sirius staring at one another. "We can do this in the morning, you're likely tired…"

Sirius groaned audibly. "Let him speak, Mary." The tall, dark haired man shook his head exasperatedly before turning towards Leo, allowing the teenager to get a proper look at the fugitive. His eyes were baggy, though there was a true happiness within the grey orbs. His hair was long and scraggly, while his beard looked unkempt. Immediately however Leo thought that he could see himself in the older man, a thought that made him look back towards his mother, wondering how she managed to cope all these years… "I understand if you want to shout and be angry." Sirius continued, drawing Leo's attention back.

"I'm not angry." Leo told him, his voice deadpan and not betraying the whole host of emotions that were completely drowning his brain.

That statement clearly surprised Sirius however. "You're not?" He asked, his eyes widening and Leo noticed a glimmer of hope within them.

Leo shrugged. "I was told you'd died. I grew up as the kid with no dad and that was fine, I had my mum and I had Grandad, I didn't actually need a dad."

Sirius winced, the mirth in those grey eyes dimming almost immediately. "I thought about you every day, I swear." He insisted.

"Thinking about isn't being there." Leo retorted quickly, before he closed his eyes and winced at how harsh it had sounded. "Sorry, that's not fair."

"No, you're absolutely right." Sirius sighed. "I had a good life; one I was truly excited for going forwards despite everything that was going on and I let my emotions get the better of me that night. Though you don't know what it was like…"

"Don't do that." Mary snapped at him, her eyes glaring daggers. "He's not a kid anymore, don't belittle him."

Sirius's mouth curled in a growl as he turned to Leo's mother. "Give me a break Mary, I'm trying here…"

"Tell me what it was like." Leo asked quickly, stopping the argument before it brewed up again. "Not the kid friendly one. The entire, uncensored truth. Let me understand why you did what you did."

Sirius sighed, looking between Mary and Leo for a moment before he nodded at Leo. "Fine… we had friends disappearing and we were losing the war, so everybody was scared out of their skin not knowing who would be next, worrying about their friends and family... then not long after you were born James and Lily… Harry's parents that is, they had to go into hiding too. He was my best friend, you understand? So naturally I was chosen to be secret keeper." He paused for a moment, the memory fresh in the man's eyes and Leo thought he saw them glisten with moisture. "I thought I was too obvious a choice though, everyone knew that me and James were like brothers and I'd be the most obvious target for You-Know-Who, and while I would never betray them I'd seen enough torture in my life to know that there had to be a better way without myself being stuck in hiding too, so I suggested Peter." He sighed, taking a minute to have a sip of his drink. "I'll regret that for the rest of my life."

"It wasn't your fault Sirius; it was an excellent idea in theory." Mary said soothingly, her prior anger having evaporated quickly, and Leo knew his Mum well enough to see that her tone was one of caring, that even after all this time and all those arguments she still cared about the man in front of the pair of them.

Sirius rolled his eyes, clearly having had that discussion multiple times. "Anyway, I'd agreed with Peter that every other day I would check up on him at his place, just to make sure he was alright and hadn't been captured or anything. It was often brief; I had a girlfriend and kid to get back to after all." Leo felt a wave of something that felt like genuine affection for the man then, and let him carry on his story. "On that night… I went round there and he wasn't there when he should have been. Instantly I knew something was up. He hadn't been taken in a fight, everything was too normal for that and there was no trace of restorative magic. So I instantly went to James and Lily's and…" He trailed off, wiping his eyes of the now noticeable tears. "The house was a ruin and Hagrid was walking outside with Harry in his arms. I tried to take him, but Dumbledore had other plans…"

Leo instantly imagined a new life, one where Harry was basically a brother to him having grown up together. It felt strange given the past 4 and a half years. "So with Harry safe you tracked Pettigrew down?" He surmised, eager to move the story along and not get caught in what ifs.

"You should have come home." Mary said sternly.

"I should have." Sirius agreed quickly. "In hindsight obviously I would have, but in that explicit moment I just felt pure anger. My best friend was dead because of a mistake I had made, and I had to fix that."

"So you found Pettigrew and fought him?" Leo guessed.

Sirius snorted. "Fought? The coward took one look at me and screamed loudly that I'd killed James and Lily, that I was the traitor. Then he blew up the street and cut of his finger, escaping as the filthy rat he was. I was dumbfounded… angry at Peter and angry at myself. Then the Aurors came and I was taken straight to Azkaban. I didn't even have a chance to speak to either of you."

Leo noticed he genuinely looked upset at that, but on top of the revelation his mind was spinning with the addition of all the new information. "You didn't even get a trial?" He asked, horrified at the thought.

Mary shook her head. "I tried, but nobody would listen to me at the Ministry and I had you to worry about. It was considered such a clear-cut case and the Ministry were so jubilant over the end of You-Know-Who that it apparently wasn't worth it to actually find the truth."

"So there I was for twelve years locked away behind bars in the worst place in the world. I thought that was it, that my life was over and I would never get to see you grow up, until one day Fudge brought a newspaper into Azkaban and I saw the rat on the front page." Sirius explained bitterly.

Leo had to think back for a moment before he remembered the paper in question, the one that had shown the Weasley family after winning the lottery that he had shown his Grandad one summer day before third year. "Ron in Egypt." Leo whispered.

"Exactly. They mentioned that the youngest few were students at Hogwarts and I knew that you and Harry were in danger." Sirius explained. "I got out, and I came to Hogwarts to try and keep you safe."

Leo snorted as he remembered more about his third year now that he was thinking on it. "You didn't do a good job; the entire school thought you were there to murder Harry."

Sirius smirked. "Hogwarts always did have a way with rumours." He sighed again and his face grew serious. "I swear, I didn't want to leave you."

"I believe you." Leo said honestly, the quick statement another surprise to the elder man. He looked between his parents, the realisation starting to dawn that he had a brand new reality now. "This will take a lot of getting used to of course, but I get it."

"You do?" Sirius asked, looking delighted.

"Yeah." Leo nodded affirmingly. "You're an idiot for rushing in blind don't get me wrong, but I get it. Your friend had died and you wanted to make it right."

Sirius nodded as well, a grin starting to show on his face at the words Leo was saying. "Exactly."

"I'm not saying this won't be weird, or that we'll have a perfect father son relationship. I've lived my whole life without you after all and this is so new." Leo made sure he said, seeing the grin slightly dim. "But I feel like a weight has been lifted, you know? Like there isn't this big gap in my life anymore."

Mary sighed, moving to hug Leo from behind. "I'm so sorry I kept it from you." She whispered in his ear.

Leo shook his head as he turned and reciprocated the hug, squeezing her tightly. "You did what you thought was right." He insisted, before another question popped into his head. "Did you think about talking to me at all that night you broke into our common room?" He asked after letting his Mum go and turning back around.

Sirius sighed, shaking his head with a light chuckle. "I didn't want to scare you and I knew I didn't have long. I knew you were there of course, but I knew you had your mum's name and guessed that my part in your life was obviously being hidden from the world… and also my hungry, vengeance filled brain thought I just needed to get in, kill Wormtail and get out again before I was spotted."

Leo just nodded, expecting that sort of answer. They stayed there in silence for a moment until he looked at the clock and saw how late it was getting. "I think I should head up to bed."

Mary smiled, kissing him on the cheek. "Goodnight love." She said.

"Night." Sirius smiled over at him. "And Leo?" Hearing his name come from the mouth of his Father sent tingles down his spine. "Thank you."

Leo nodded. "We'll talk tomorrow." He replied, giving his Father one last look before turning around and heading out of the door, rushing straight past his gawping classmates as he ran up the stairs.

It had been such a long and draining day with all of the travelling and the truth finally being out there, but despite feeling extremely tired Leo couldn't drift off to sleep. It wasn't even the loud snoring coming from Ron's direction that was keeping him awake, nor was it Harry's constant writhing in his bed from whatever nightmare the Boy-Who-Lived was inevitably having as he was used to both of those while in his dormitory at Hogwarts. This time, he felt restless as he kept replaying the last few hours over and over in his mind until the entire night had seemed to pass as he noticed the sun beginning to appear through the dusty curtains. Sighing and knowing that the amount of people within the house would make sleep impossible soon, Leo got out of bed and as silently as he could, left the room.

He didn't know where he was going, but almost immediately after he had turned away from the room he was sharing with his classmates he heard more footsteps. Turning, he spotted Harry. "This way." Harry insisted with a nod, leading Leo down the stairs to the first floor. He entered the drawing room and saw Harry immediately point up at the tapestry adorning the walls. "Once you ran off yesterday Mrs Weasley dragged us inside the Kitchen and ordered us to keep the noise down… then your mum told us that Sirius is your dad and that you didn't know until then."

Leo nodded. "That still feels strange to hear out loud. Yesterday Sirius Black was a murderer that was on the loose, today he's innocent and he's my dad?"

Harry let out a snort of amusement. "Yeah I can imagine, it's all mad isn't it? I remember when I found out he was innocent. I was convinced that he was the traitor that got my parents killed and was ready to attack him, then the next minute he was telling me that he was my godfather and that I could live with him if I wanted."

Another wave of jealousy hit, a usual feeling when it came to Harry but this time it stung just that little bit more as Leo wondered on what it would be like if he was the one to live with Sirius. "Did he mention me?" He asked, internally grimacing at how childish he sounded.

Harry thankfully didn't seem to notice that and simply shrugged. "He asked about my classmates. Now I think he was just feeling out information, but when I said your name he didn't press for anything more."

Leo understood why. "I have my mother's surname." He explained Sirius' words from the night before. "He probably knew that mum kept him a secret."

"For the best, right?" Harry asked.

Leo shrugged. That was one of the main questions that had kept him up all night, trying to understand if he would have been better off as he was, or if knowing the truth despite the stigma that would have followed would have been better. "We'll see." He muttered. He turned to the tapestry looking around at all of the names. He spotted an infamous Hogwarts Headmaster quite quickly. "So am I on here?" He asked.

Harry shook his head, pointing over to a scorch mark on the wall not too far away from that Headmaster. "Sirius was blasted off… I'll let him explain the story. But no, the magic connecting him to this room was severed."

"Ah." So it was like he had never existed. "I really don't know what to think." He admitted.

It was probably about as vulnerable as he had ever been in front of Harry, and it was clear that he noticed it too. "I felt the same when I found out I was a wizard. One minute I was a strange muggle that was hated by his family, the next minute I'm famous in an entirely new world." Harry chuckled. "I'm still adapting to that; you'll do so quicker I'm sure."

"Let's hope." Leo nodded. "Thanks, for this." He spread his arms around the tapestry room. "I've only ever really had my mum and Granda', so this is overwhelming, but nice to know where I've come from."

Harry shrugged. "I've not had a proper family for so long that when Sirius came around it was overwhelming too, like I had some form of family again. I do feel bad that he never got a chance to be that for you before now when he's had a couple of years getting to know me. He's a good man, honestly."

"I can feel that." Leo agreed, though he was still a little unsure what to make of his newly returned paternal figure. "It's all still so new."

Harry nodded, gripping Leo's shoulder and squeezing. "You'll get used to it. And I know I may not always be the most open of people, but I know about this, so if you ever need to talk I'll try not to snap your head off."

Leo grinned. "Thanks." He said, and Harry nodded the once before leaving Leo alone in the room. Leo looked at the scorched mark detailing Sirius on the tapestry and began to trace his finger back, learning all about this brand-new family that he had gained.

After that first night inside Grimmauld Place, Leo had started to feel a little bit more settled. Whilst it was a bit awkward for Leo to be around Sirius the other Hogwarts students clearly felt at ease and relaxed around the fugitive and the run up to Christmas was mainly spent with a brief trip with Mary into Diagon Alley for some last-minute gifts for everybody he was now staying with for the holiday, and also decorating the grubby and dark house into something vaguely resembling an extravagant Christmas grotto and Leo had had far too much enjoyment placing Christmas hats and beards onto the stuffed elf heads.

Leo woke up on Christmas Morning to see Harry and Ron sat on the floor of their room, already mostly through opening their own presents. "Morning Leo." Ron said happily, putting on a woollen Christmas jumper with his first initial in the middle.

"Morning mate." Harry added, grinning as he let a model firebolt whizz around his head. "Your presents are there." He pointed to the foot of his bed.

Leo usually opened everything a bit later on with his mum, but whilst he looked through his modest pile he noticed that her gift wasn't actually there with a note in Mary's handwriting saying to open these ones now. Shrugging, Leo did as he was requested and ripped into the gifts, noticing one from Hermione first, a homework planner. Opening it, Leo was amused to find it spoke to him. "Don't leave it till later, you big second rater!"

"She got you one too?" Ron asked, horrified. "I'm so sorry mate…"

"No, it's cool." He chuckled, placing it to one side with a smile. "I needed a new one…"

Ron was even more horrified at that statement. "You're mental." He said, turning his face into a smirk.

Leo snorted in amusement as he turned to some of his other gifts. He got some sweets from all of the Weasley kids and a book on Ancient Wizarding Families from Harry. Professor Lupin had given him an annotated version of his third year Defence Against the Dark Arts textbook with additional tips and pointers, but then Leo spotted gifts from his friends. Fay had managed to get a couple of presents over to him, a new Wigtown Wanderers Gobstones set and some chocolate frogs, while Anna had sent him an edition of Witch Weekly with an interview from Kennilworthy Whisp, the author of Quidditch Through the Ages. His last gift in the pile came from Mrs Weasley, who had knitted him a silver Christmas jumper with a black L in the chest.

"You best put that on." Harry noted holding a painting of himself judging by the scrawling on the back. "It's a Weasley tradition…"

Speaking of Weasley's, a loud crack sounded making Leo drop his jumper and the twins appeared at the foot of Harry's bed. "Merry Christmas." George said, Leo presumed because of the big G on his own jumper. "Don't go downstairs for a bit."

"Why not?" Ron asked.

"Mum's crying again." Fred explained to them. "Percy sent back his Christmas jumper."

"Without a note." George added. "Hasn't asked how Dad is or visited him or anything…"

"We tried to comfort her." Fred told them. "Told her Percy's nothing more than a humungous pile of rat droppings…"

"Didn't work." George interrupted, tucking into a chocolate frog that he had stashed in his pocket. "So Lupin took over. Best let him cheer her up before we go down for breakfast, I reckon."

"What's that supposed to be anyway?" Fred asked, pointing at the painting. Leo tried not to laugh when he saw what the painting of Harry looked like, and with a grin he got up and put the jumper on, leaving the room to go and find his Mother.

On the way out he almost bumped into Hermione and Ginny, neither of whom were wearing a matching jumper. Ginny just laughed at him but said. "Thanks for the sweets… and sorry." She nodded to the jumper before walking away.

"Great." Leo muttered. "They told me it was tradition."

"It is, for the boys I think." Hermione shrugged. "Ginny never wears hers if she even gets one." She then looked up at him with a smile. "Thank you for the Bridget Wenlock book by the way, she's a fascinating historical figure..."

Leo had known Hermione was interested in her through their Arithmancy lessons, though choosing the right present for her had been the toughest challenge of all as he wondered if it was too obvious, or too personal, or a whole host of other worries in the middle. "I read it a couple of years ago and found it fascinating. I wasn't sure if you had read it or not when I got it but…" He trailed off.

"It was thoughtful." Hermione smiled. "And I haven't, so thank you! I'm looking forward to opening it already."

"I opened the planner." Leo grinned at her. "It's very loud."

Laughing and nodding, Hermione added. "It's meant to be! It's there to remind you to do things. Not that you need reminding of course, you're normally as on time with homework as I am I just didn't know what else to get you…"

"It's great, I really needed a new planner." Leo explained, stopping her from starting a fast-paced, nervous rant. "Thank you, seriously." He said honestly, admiring her smile as she tucked her hair behind her ear.

"Hermione!" Ginny called from the floor below.

"Coming!" Hermione called back, before looking over at Leo once more. "Are you coming to St Mungo's today?"

Leo shook his head. "No, I don't know Mr Weasley so I'd feel a bit weird about taking up a visiting space. Best I stay here out of the way."

"Oh of course. That's considerate of you." Hermione nodded. "Well, I'll see you later?"

Leo smiled over at her. "Sure." They stood there for a moment not saying anything when Hermione tucked her hair behind her ear with a smile and turned to descend the stairs. Leo went to lean against the wall for just a moment before he went to walk to his Mother's room, but before he could move 5 paces he spotted Sirius Black coming his way with a grin.

"Smoothly done." Sirius said with a smirk. "She's a nice girl."

Leo didn't like the tone that was used and frowned. "Yeah, she is." He said shortly. "Sorry, I need to find Mum."

Sirius nodded, but his eyes quickly lost their joviality. "Downstairs, drawing room." Not wasting any time with any more words or a farewell, Leo briskly walked away and down the stairs, eager to find his Mum and wish her a Merry Christmas.

Once the majority of the house's current occupants had gone to visit Mr Weasley in the hospital Leo and Mary moved into the kitchen to start on some of their own, personal traditions while it was quiet inside Grimmauld Place. Together they laughed as they made Christmas themed scotch pancakes and absolutely drenched them in syrup before they began opening presents. Mary had bought him some new clothes as well as the brand new Wigtown Wanderers jersey, which Leo very quickly put on instead of his Weasley Jumper, while Leo handed over the liquorice wands he had got from Hogsmeade a couple of months earlier and a rather nice locket in the shape of a Creaothceann bucket.

The door swung open as Leo was about to tuck into his breakfast and Sirius came through the door, looking alarmed to see them. "Sorry, I thought you were…" He trailed off, looking behind him. "I'll go."

"No, don't." Mary sighed. "It's Christmas, and if this is going to be the new normal, we may as well get used to it." She looked at Leo. "Is that ok?" Leo just nodded, and so Mary got up and put some of the extra pancakes on a third plate. "Come, Sirius. I remember how much you liked these."

Leo was surprised. "You spent Christmas with Gran and Grandad?" He asked without pausing to think.

Sirius chuckled at the rash question. "Yes, the first year after we finished Hogwarts. We'd just started planning on moving in together, hadn't we?"

"Aye." Mary nodded. "And you wanted to get Da's blessing." She snorted and looked at Leo. "Well, you know what Granda' was like."

"We could have his blessing and some money towards the house so long as I beat him at the game he liked." Sirius was reminiscing fondly with a grin adorning his face. "I lost. Handsomely."

Mary grinned. "But the fact you indulged him warmed him up to you. He helped us get that little cottage." She sighed. "He never believed the stories after you were arrested, always said you weren't that sort of person."

"Magnus was a good man." Sirius said solemnly, before sighing heavily. "I really am sorry I wasn't around for either of you. I honestly did think of you both every single day after it happened."

"You should have thought about us on the day." Mary said firmly, her Scottish accent heavy. "Honestly… when I heard about that after Lily and James… That really was the worst day of my life."

Sirius nodded. "It's my one regret." He said quietly. "When I first met Harry and thought on what could have been… us four all together, happy."

"We can't dwell on the past." Leo said calmly. "But, for what it's worth, I didn't have an unhappy childhood. I always wondered who you were of course, but it never affected me too badly because I didn't remember you if that makes sense. Now I have the chance to get to know you better and to build a relationship."

Sirius smiled, touched by the words. "You mean that?"

Nodding, Leo honestly did. "I do, and I can't speak for Mum but I guess I forgive you. It might take some getting used to as Mum says, but I'm ready to try."

Sirius grinned and clasped Leo on the shoulder. "Thank you." He whispered.

"And you can start by telling me what Mum was like at school…" Leo smirked, causing Mary to protest and Sirius to bark into laughter.

The others came back hours later where the three were still sat in the kitchen listening to tales of Hogwarts from his parents' time at the school, and Leo was very hopeful that all would be well.

Reviews:

AZW330: I'm glad it was a surprise for somebody at least! That's something I really wanted to achieve with this.

Asta0213: Thank you! I'm glad you seemed to be surprised by it.

Dante687: Too many OC's, even Canon OC's (canon characters that are basically just a name so their fic personalities are effectively original) can bog down the story, and I really wanted to tie Leo to Harry and the others in a bit more of a natural way.

1shinChan: Thank you! Everything in this story I believe will be from Leo's perspective. I don't think that will change but I'm not 100% sure of that.

SkepticPrinceArthur: Thank you! If I'm honest Lupin being the one to appear is based on the below line from Goblet of Fire, it made the most sense out of the mentioned characters.

"That will do to be going on with," said Dumbledore, stepping between them once more. "Now I have work for each of you. Fudge's attitude, though not unexpected, changes everything. Sirius, I need you to set off at once. You are to alert Remus Lupin, Arabella Figg, Mundungus Fletcher — the old crowd. Lie low at Lupins for a while; I will contact you there."

As for the OC portrayals, I have an idea in my head… to me Leo is young Ben Barnes, Mary is Emily Blunt, Fay is Madeleine Duggan while Anna is a younger Olivia Cooke. That being said, I'm not holding the audience to those.