Using Crucio on Harry would completely transform their relationship. Harry would be traumatized by the experience, and his view of Draco would be forever tainted. He'd see Draco as a heartless bully who is willing to use the darkest of magic. Draco, by doing this, has put himself in a position where any potential for friendship or even a civil relationship is gone. It would be the start of a long - running enmity, with the memory of the Crucio spell always lingering between them, fueling their animosity.
The spanking could be a turning point. It could be a catalyst for them to start communicating more openly. Maybe Draco spanks Harry as a way to get his attention because he has something important to tell Harry about a threat in the wizarding world. This leads to a series of interactions where they gradually build trust and respect for each other.
In many of these fanfics, the relationship is a slow - burn development. Draco's initial control is more about power and showing superiority. However, as time goes on, they are forced to interact more closely. This might lead to Draco seeing Harry's vulnerability and Harry seeing Draco's hidden kindness. They could then start to form a bond that is based on shared experiences while under this strange control dynamic.
It could lead to a more amicable relationship. Draco might be initially shocked and then grudgingly grateful. This could start to break down the walls of their enmity. They might start to interact in a more civil way, like nodding at each other in the hallways instead of glaring.
At first, they might be shocked and a bit confused about being twins. But as time goes on, they start to trust each other more. They could share their secrets and fears, like Harry might tell Draco about his nightmares of Voldemort, and Draco might open up about the pressure from his family.
It often changes for the better. After Harry apologizes, Draco might be initially skeptical. But as they start to interact more, they could become friends or at least develop a mutual respect. For instance, they might start sharing their experiences during the war, which helps them understand each other better.
At first, it's likely to be full of hostility. Draco would probably enjoy lording over Harry as his slave, and Harry would resent it. But as the story progresses, they might start to understand each other better. For instance, Draco could see Harry's strength and determination even in his slave position.
At first, it's likely to be very tense. Draco would be suspicious of Harry's motives for protecting him. He might think it's some sort of trick. But as time goes on, they start to understand each other better. Harry realizes that Draco isn't all bad and Draco sees that Harry is genuinely trying to help. This could lead to a grudging respect between them. Eventually, they might even become friends, or at least allies.
At first, it would become more strained. Harry would likely be angry and hurt by Draco's actions that made him cry, so he might avoid Draco even more than before. He might also be more on guard around Draco, not trusting him at all.
Towards the end, their relationship could become a very strong and unique one. They could be each other's closest confidants, with Harry being the one Draco turns to when he has doubts about the pure - blood ideology, and Draco being the person Harry trusts to keep him safe in the Slytherin common room. Their bond would be a mix of brotherly love and mutual respect.
Well, in such a fanfiction, the relationship between Harry and Draco would likely be a complex reimagining. Since Harry is seen as Salazar and Draco as Godric, they might have a relationship based on the historical enmity and respect that Salazar and Godric had. They could be rivals, constantly testing each other's skills and knowledge, yet also having a grudging respect for one another due to their 'founder' status.