He would likely be more stealthy. Natasha is known for her ability to move quietly and unnoticed, and Harry could inherit this trait. He might also be more physically fit and have better combat skills than in the original series.
Yes, it is possible. The combination of the magical world of Harry Potter and the spy - like skills and background of Natasha Romanov can create a very interesting and unique plot. For example, Harry could inherit some of Natasha's combat and espionage skills, which would be very useful in his battles against the dark forces in the wizarding world. He could use his stealth and combat abilities to outwit his enemies in a different way compared to the traditional magic - only approach in the original Harry Potter series.
He would be more physically capable. Natasha's training would make him better at hand - to - hand combat compared to the original Harry. He might also be more confident in dangerous situations.
She could be more resilient. Growing up as a black in a predominantly white wizarding world might have toughened her up. She may also be more community - oriented, drawing on the strong sense of community often found in black cultures. And she might be more in touch with her emotions, not suppressing them as much as the original Harry did.
Lemon could be brave like Harry. Since they are twins, she might inherit the same Gryffindor - like courage. She could be the type who doesn't shy away from standing up to bullies at Hogwarts, just like Harry does with Draco Malfoy.
One potential ally could be Hagrid. Hagrid has always been a friend to Harry, and in this fanfiction, he could help Harry understand his newfound heritage as the son of Hephaestus. Hagrid's knowledge of magical creatures could also be useful in Harry's adventures related to his Hephaestus - given abilities.
Hermione would definitely be one of his allies. She is smart and would be able to help him research about his new identity and how to control his powers. For example, she could find ancient texts in the Hogwarts library that relate to both the wizarding world and the Greek gods.
In this fanfiction, some of the potential allies for Harry could be the magical creatures that have a connection to Norse mythology. For example, the Valkyries. They could help Harry in battles or in understanding his new heritage. Another ally could be Odin, Frigga's husband. Despite the initial shock of Harry's existence, he might see the value in Harry and offer his protection and guidance. And don't forget Neville. He's always been a loyal friend to Harry, and in this new scenario, he would continue to be an ally, perhaps even more important as Harry faces new and different challenges.
His friends from Hogwarts could still be his allies. Hermione would use her intelligence to help him understand his new situation. Ron would be there for moral support. Additionally, any friends or allies that Rias has in her world could also become Harry's allies. They might be magical creatures or other powerful mages.
Hermione would definitely be an ally. She's smart and would be able to help Harry research about his 'son of Mars' heritage, finding ancient spells or texts that could explain it further.
He would probably be highly intelligent. Mycroft is known for his brilliant mind, and Harry would likely inherit that. He'd be able to analyze situations quickly and come up with solutions. Also, he might be more introverted compared to the original Harry. Mycroft is not a very outgoing person, so Harry could be more reserved, spending time thinking and planning rather than being in the spotlight all the time.