His relationship with Sirius would be extremely strained. Since Walburga was Sirius' mother and they had a very difficult relationship, Sirius would likely see Harry as a product of his mother's influence. Harry, on the other hand, might be initially hostile towards Sirius due to being raised with Walburga's views.
In the case of Harry being raised by Walburga Black, his relationship with Sirius would be full of tension. Sirius had a lot of negative experiences with his mother. Harry, growing up under Walburga's care, would be influenced by her beliefs and values. This means that Harry might not understand Sirius' reasons for leaving the family. Sirius, in turn, would be skeptical of Harry's loyalty to the 'right' side, considering his upbringing. However, as they get to know each other better, they could potentially find common ground and start to build a new relationship based on mutual understanding and a shared desire for a better wizarding world.
If Harry was raised by Walburga Black, his relationship with Hogwarts would be drastically altered. Firstly, he might enter Hogwarts with a preconceived notion of his superiority due to his pure - blood upbringing. He could look down on some of the traditions that were inclusive of all blood types. His loyalty to Hogwarts as a whole might be divided. He would likely be more drawn to the Slytherin ideals which are more in line with Walburga's beliefs. He might not form the same close - knit group of friends from different houses. Instead, he could be more focused on building relationships with pure - blood students from Slytherin or other houses who adhered to similar values. His view of Hogwarts as a place of unity and acceptance would be clouded by the pure - blood ideology he was raised with.
His life would be quite different. Walburga was a strict and proud pure - blood. Harry might grow up with a stronger sense of pure - blood superiority drilled into him. He could be more proficient in dark arts - adjacent magic earlier as Walburga was from the Black family which had some connections to such magic. However, he would also likely face more internal conflict as the values of Hogwarts and his friends would clash with what Walburga taught him.
Harry would likely become more confident. With Sirius as his guardian, he'd have someone who truly believed in him from the start. Sirius was brave and rebellious, and these traits could rub off on Harry. He might be more willing to take risks and stand up for what he believes in earlier in life. For example, he might not tolerate the bullying from Draco as much as he did in the original story.
Harry would likely be more confident. Sirius is a bold and brave character, and growing up with him would instill those qualities in Harry more strongly. He wouldn't be as meek as he was in the early days at Hogwarts.
The plot would change drastically. Harry would not be living with the Dursleys, so there would be no need for him to escape that horrible situation. Voldemort might have a harder time targeting him as his parents would be on high alert. There would be no letter - hunting drama. Also, his relationship with Snape would be different as his father was Snape's rival. His parents could have taught him some advanced magic from a young age, which would make him stand out at Hogwarts in a different way than in the original story.
The story of Fem Harry Potter raised by Sirius Black could be full of twists. Sirius would have to hide her from the Ministry and Voldemort's followers. This would mean a life on the run at times. But it also means she'd be more street - smart in the wizarding world. She might grow up with a love for Sirius' motorcycle and a sense of adventure. Her time at Hogwarts would be different too. She'd have Sirius' stories in her head and might question the school's rules more often, leading to some interesting situations with the teachers.
On the other hand, he could become more powerful and confident in his magic earlier. Walburga might push him hard in his magical studies, and with her knowledge of the Black family's magical heritage, Harry could develop a more assertive and perhaps even a bit of an arrogant streak in his magical abilities. But at the same time, he would also have to deal with the internal conflict of the Black family's dark past.
Harry's relationship with the Weasley family would change. Mrs. Weasley might be a bit more hesitant in accepting him at first, worried about the Black family's reputation. But over time, she would warm up to him. The Weasley twins would see him as an even better partner in pranks, given Sirius's reputation for mischief. And Ginny might have a different kind of crush on him, seeing him as more of a rebel and being attracted to his new family - related boldness.
Well, at first, Sirius would be in a state of shock and panic. But then he'd have to step up. Their relationship would shift from one of equals (in a sense, as Harry was growing up) to a caretaker - cared - for dynamic. Sirius would have to learn about Harry's likes and dislikes as a baby. He'd sing lullabies to him, comfort him when he cries. This new experience would make their bond stronger in a very different way. Harry might not remember all of it when he's turned back, but there would be a subconscious change in how he feels towards Sirius, a deeper sense of security and love that stems from those baby - days when Sirius was his whole world.
Well, if Harry Potter was raised by Thor, his character would likely be more bold and fearless. Thor's warrior - like nature would rub off on Harry. He might be more upfront in facing challenges instead of being a bit hesitant as he sometimes was in the original series. Harry would probably have a different view on magic too, seeing it more as a powerful tool like Thor views his hammer, rather than just a means to an end in the wizarding world.