In some fanfictions, handcuffs and shackles might be used symbolically. For example, they could represent the constraints Hermione faces in a dangerous or restricted situation. It could be in a plot where she's wrongly imprisoned by dark forces, and the handcuffs and shackles are a physical manifestation of her captivity. This creates a sense of tension and the need for her to use her wits to escape.
One interpretation could be as a sign of oppression. If Hermione is in a story where there is a tyrannical regime, the handcuffs and shackles might be used to show how she is being silenced or restricted. It's a way to create a sense of injustice that she will then fight against.
Yes, there might be. The Naruto and Attack on Titan fandoms are both huge, and fans often like to cross over their favorite characters in fanfiction. So it's quite possible to find Eren - from Attack on Titan - in Naruto fanfiction. However, it may not be as common as fanfictions within each respective universe.
Some fans are heartbroken. Eren is a very popular character, and his death can be a huge emotional blow. They might write comments expressing their sadness and disappointment.
Fanfiction about Eren and Levi kissing can be quite interesting. It might explore a different side of their relationship. Some fanfictions in this regard could be about a moment of emotional intensity between them, where the kiss represents a deep connection that goes beyond their usual interactions in the original story.