One possible motive could be to create an emotional shock for Harry. It makes him face a difficult situation and tests his moral compass. Another motive might be to force Draco to reveal some important information, with the torturers knowing that Harry's presence would add extra pressure on Draco.
Well, in fanfiction, it could be a way to manipulate Harry's actions. By torturing Draco in front of him, the antagonists might hope to make Harry angry enough to do something rash, like give away his location or a secret. It could also be about power play. Showing that they can harm someone close to Harry (even if Draco and Harry are not exactly friends) is a way to assert dominance over Harry. And perhaps it's a way to break down the barriers between the Gryffindor and Slytherin houses in the context of the fanfiction, by making Harry and Draco share a very intense and life - changing experience.
This kind of scenario in fanfiction often plays on the emotions of the readers. It might make Harry seem more heroic as he could potentially try to stop the torture. On the other hand, it could also show Draco in a more vulnerable light, which is different from his usual haughty self. The fanfiction author might be using this situation to build a bridge between the two characters, who are often on opposite sides in the original series. It could also lead to a whole new arc in the fanfiction where they team up against a common enemy because of this shared traumatic experience.
It could be out of disappointment. If Draco fails to meet Lucius's high expectations in terms of upholding the family's pure - blood status or in his performance at Hogwarts, Lucius might resort to violence as a form of punishment.
Well, Bellatrix is a very complex and cruel character. In the fanfiction context, she might torture Draco to assert her dominance. She is a powerful and deranged Death Eater, and by torturing Draco, she can show that she is in control. Also, it could be related to her pure - blood mania. If she thinks Draco is not living up to the pure - blood standards in some way, she may take it upon herself to 'correct' him through torture.
Maybe it's a form of power play. By taking Harry's glasses, Draco is asserting his dominance. In the wizarding world, status and power are important, and this could be Draco's way of showing that he can take what he wants from Harry, who is often seen as his rival.
Yes, there might be such fanfictions out there. The Harry Potter fandom is vast, and fans often explore dark and dramatic scenarios in their works. However, these can vary greatly in quality and adherence to the spirit of the original series.
One possible motive could be that Draco wants to annoy Harry. Stealing his glasses is a petty way to get under his skin. It's a simple act of mischief that Draco might think is funny. Another reason could be that Draco is jealous of Harry. By taking something so important as his glasses, he feels like he has some power over Harry.
One thing to keep in mind when looking for such a fanfic is that it might be a bit hard to find as it's a rather specific and dark concept. Some fanfic writers might be hesitant to write about such extreme torture scenarios. You could also check fanfic communities or forums dedicated to Harry Potter. Post a request there asking if anyone knows of a fanfic with this plot. Maybe someone has come across it or has even written one themselves.
There could be themes of trauma and recovery. If Harry is tortured in front of Ginny, both of them would likely experience significant trauma. The fanfiction could explore how they deal with that, both individually and as a couple. Also, themes of loyalty and friendship might be present as their friends try to rescue Harry.
It could also be for power. Some evil shinobi might believe that by capturing Naruto and somehow extracting the Nine - Tails' power, they can become extremely powerful. They might have some sort of dark jutsu or experiment in mind that requires the power of the Nine - Tails which is sealed within Naruto.
Another motive could be revenge. Maybe some in Iwa still hold grudges against Konoha for past conflicts. Since Naruto is a prominent figure in Konoha, kidnapping him would be a way to strike back at the village. They might think that by harming Naruto, they can make Konoha suffer.