Disclaimer: I don't own Harry Potter.

Notes: This work will be mostly about sexual themes on the darker side, such as domination and manipulation. If you don't like such themes, you shouldn't read. And lemons, lots and lots of lemons. This story will contain dark themes like killing and rituals.

"Ughh!"

I woke up from slumber and was greeted with bars and a dingy room. Looking around and noticing the horrendous atmosphere, I can only conclude that I am not where I am supposed to be, and the room or place appears to be a jail cell. Trying to stand up so I could move my muscles, aches, and cramps came in, and I fell.

"Fuck!" I cursed.

Looking at my hand and feet, I can say I wasn't kidnapped but experienced the so-called transmigration, so my soul got shafted in another body. I know I didn't die because I was going to sleep one moment, then I was here. I didn't even experience breathing problems when I laid down, so only a 'ROB' would be responsible for my placement here for his entertainment. I might have died and been sent for the mission, but I got my memories erased who knows, though first I need to find my current predicament or my bodies identity and finally get out of jail. Who would spend their second chance in a dingy jail.

"Keep it down, black; your betters are trying to sleep."

"Hahahahaha"

"Leave the blood traitor alone; maybe he dreams about his dead mud-blood lover boyfriend."

"Hahahahaha"

Hearing the jeers, I crawl forward despite the pain, peer through the bars, look at both sides, and see my fellow prisoners doing the same while laughing at my predicament. Through their jeers, I have already guessed who I am and which world this is. The surname black gave it away, while the mudblood lover would be James, so I am Sirius Black. As the realization came, pain shot through my head, and even the hair on my new body decided to make it worse, as it felt like my nerves were on fire. Confusion swept my very being as torrents of 35 years of memory came; my previous self was only 45 years old, so I had to wrestle for identity control as I didn't want to lose myself and become an amalgamation of Sirius Black.

"Huff HuFF Huff"

Opening my eyes, I feel myself lying on the ground; I drag myself back and take deep breaths to calm myself. Taking a deep breath, I try to meditate, and slowly but surely, I feel and experience the memories of the now-deceased Sirius Black.

A rigorous childhood training while being blatantly tortured by a wretched witch Walburga Black. Recalling several dark spells, the mind-numbing repetition, and ways to enforce those spells in fights—the bonding with a little brother and failing, and then getting fed up and trying to be different from the loveless family to then getting into Hogwarts and being defiant and as a middle finger to the parents, getting into Gryffindor, experiencing love and friendship for the first time and becoming an animagus and running away to live with Jame's family and then a dark lord coming to destroy the happy life that was finally there. Then fighting against him, eventually being named a godfather of a green-eyed little girl, betrayed by a disgusting rat, and ended up here.

Experiencing these memories did a number and forced me to live with several emotions, mainly disappointment and sadness. Mainly with myself, I felt betrayed by someone I so dearly trusted. In my previous life or self, I became a mercenary for the quick cash and mostly to have a fun life, as I wouldn't say I liked the usual 9-5. Over 17 years of my career, I experienced all first kills, close death calls, but most of all, betraying or sacrificing people so I could continue to live. I knew I could die on a mission or a stray bullet. Still, I always got scared feet and looked for ways to prolong the inevitable and ultimately betrayed my mercenary group to get it on with a better company called Black Water. Being selfish and putting yourself first always feels right, but now I feel how my comrades felt after being betrayed. Feeling like a piece of shit, I contemplate my previous actions before slapping myself.

"Focus"

Through the memories, the thing that stood out like a sore thumb was Harry Potter being a girl and Hogwarts starting at 18, and most of all, Lily was twitching, meaning she experienced Cruciatus Curse and is alive. As she didn't come for Sirius, it is most likely that she is still in a coma like Longbottom's, or she forgot about him. But it is most probably the first reason.

Now my first course of action is to escape, and I will steal the idea from Sirius and use the animagus form after I get the hang of it.

It was a weird feeling like a dog; your five senses get enhanced, but you get smaller overall. I don't know if this applies to my new body can have the boosted senses. While contemplating and getting used to being a dog, I felt cold travel down my spine, and my vision blurred. Screams of my fellow inmates make it hard to focus.

"Whining"

Whimpers escaped my mouth as old and new memories of my deepest fears returned. The faces of the people I betrayed in my first life questioned me on why I betrayed them. James Potter's dead body came ahead while Peters Peter Pettigrew laughing face when he proclaimed betrayal. When I felt my happy emotions leaving me, I tried to touch anything in my body, like magic. Fuelled with desperation and a need for survival, I felt the new building energy within me. As soon as I caught that point, I pushed whatever I could toward the dementor that got too close. As the magic left me, I got my vision back, and I quickly hid the corner of the cell while making sure my back was facing the bars.

I was expecting the dementors to come and feel the usual cold, sure, the books described them as dangerous, and Sirius himself was experiencing them, but to feel the brunt of their force has put things in perspective; the magical world is scary. I gave myself just four days to escape Azkaban, and I had learned if there were any guards on this section and their timetable, most of all, remember the route of this place when they brought me in. Thankfully Sirius still had this many smarts to not morph into his animagus in front of guards, or else they would know how he was planning on escaping.

_Week Later

As soon as the guard threw the food and turned around, I morphed into a black grim, slid through the doors and jumped onto his back, and ripped his throat apart while clawing away his wand that was on his wand holster.

"What the…. Ahhhhhh motherfucking black, you are a bloody animagus….."

"Please, nooo, I don't want to die…."

Morphing back into a human and picking up the guard's wand, I instinctively threw the cutting hex on his neck and ended him. Assimilating Black memories has helped me get the same proficiency as him, though, for more complex stuff, I would need to practice it a little more.

"Hey, Blood traitor, help us… and I can help you get back into the lords good graces."

"Ah, haha... you killed him, Dumbledor's dog killed, and the old coot will be so sad."

"Hey Siri, help me escape, and we will be good, just like old times. Doesn't family come first"

Hearing the chatter, I brought my attention to my fellow inmates. Now two things are coming to my mind, killing all of them and running. But that would jeopardize all my plans. As they would know, I was the only one missing, so I did all this, second way would be taking them with me, stunned, but I can't yet do such high transfiguration like turning them all into sticks and bringing them in my pocket. Funny how I can become a dog but can't do the same to another human; maybe this body is more used to transformation than other complex magics. An idea came to mind for using the Blackhouse old elf. But I would need to get o the wards restricting the elf from being summoned.

I turn to them and start using stunners on the ten people present one by one. Their malnourishment and overexposure to dementors make them more susceptible and easy targets. Sirius was used to turning into a dog, so dementors didn't entirely damage him as the other criminals here.

"You bastard, what are you doing?!"

"Blood Traitor!"

"Bastard"

As soon the last fell, I unlocked their door using Alohomora, levitated them all out, and brought them to Rockwood's cell to create an illusion that he was the one behind this all. However, authorities could easily decipher the scene as a sham. I got out of the cell and then kept my distance. I started to dig deep to feel the well of energy in me, poured it all into the wand, and cast the blasting spell on the cell wall.

"Bombarda!"

Air simmered on my side, and a dark glow came to my eyes; a heavy feeling came upon the atmosphere as then an orange light flickered from the wand, and then I heard a loud bang with a lot of gravel and stones flying, already knowing it would affect my eyes and ears. Even though I tried to gauge the distance and keep myself safe, I still felt the impact. Knowing this would have already alerted half of all of the guards, I quickly went to the newly created hole and witnessed the waves crashing at the base of the prison and a gloomy atmosphere with all the depressing black clouds. Cutting my observation off, I transfigured the ledge and kept supplying it with magic so I didn't fall off; I already felt the magical drainage's effect after everything today. I quickly summoned the bastard and hated houself.

"Kreacher"

"As the heir sole male heir remaining of Blackline, I summon you here."

Pop!

"Blood Traitor Master called"

Not bothering to correct him, I continued to order him and made sure I used the correct wording, so he didn't pull a fast one as he lied to Harry in the books.

"Take me back to the black household, and then come back here and throw all these bastards in the dungeons. They got the news that you had something of the dark lord, and they were planning to come to get it back so that you can't fulfill Regulus's last order. Don't take orders from anyone except me."

Stunned by my words and order, he was, most of all he was shocked by how I mentioned Regulus's order.

"Hurry Up!"

He came forward and took my arms; suddenly, I felt a pull sensation on my navel, and I fell on my feet, I felt severely nauseous and wanted to throw up, but I hardly ate anything in the past week except for a few dusty loaf bread. Getting up and looking around the house I found myself in, I felt the gloomy atmosphere, and simultaneously, the disgust and sad emotions made them know where I was. I looked around and found myself staring at a portrait, also staring at me in shock.

Smiling at the now-agape face, I said

"Hello, my dear Mother."