Snape could be very cautious in his interactions. He would be constantly aware of the power dynamics. He might flatter the more powerful Death Eaters subtly to avoid suspicion. For instance, he could compliment Bellatrix on her loyalty to the Dark Lord. At the same time, he might try to intimidate the weaker ones to show that he's not to be trifled with. He might use his knowledge of the Dark Arts to his advantage in these interactions, like casually mentioning a difficult spell he's mastered to gain some respect.
Well, Snape's interactions at a Death Eater meeting could be complex. Since he's a double - agent, he has to balance between fitting in and not getting too involved. He might engage in some light banter about the latest dark magic experiments, but always be careful not to reveal too much of his own knowledge. He could also use his sarcasm as a weapon. For example, if a Death Eater makes a stupid comment, he might say something like 'How clever of you' in a very dry tone. And when it comes to discussions about attacking the Order of Phoenix, he would try to deflect attention or give false information without being too obvious, all while trying to maintain his cover among the Death Eaters.
There's also the possibility that it was an accident. Fanfiction often plays with the idea of magical accidents. Maybe a spell misfired during a demonstration or a fight that broke out among the Death Eaters that Snape got caught in the middle of, and as a result, he got injured.
He could be suspected by Voldemort. Since Voldemort is very paranoid, an injury at a meeting might make him think Snape is up to something or being careless in a way that could endanger their plans.
There are several. Some focus on Snape's early days as a Death Eater. For example, in one fanfic, it details how he was recruited, his initial thoughts on Voldemort's ideology, and how he gradually started to question it. It also shows how his relationships with his fellow Death Eaters were formed and evolved over time.
One possible plot twist could be that Snape is actually there to spy on the Death Eaters for Dumbledore, but the other Death Eaters start to suspect him. Maybe he accidentally reveals some knowledge that only a spy would know. For example, if he knows about a secret mission that was supposed to be only known within the Order of Phoenix. Another twist could be that Snape has a secret agenda of his own that is different from both Dumbledore's and Voldemort's. He might be trying to manipulate the situation within the Death Eater meeting to his own advantage, perhaps to gain some sort of power or information that could be used as a bargaining chip later. And finally, there could be a twist where a new character shows up at the meeting who has some sort of connection to Snape's past, and this changes the dynamics of the meeting completely.
One common theme is Snape's internal conflict. Since he was a double agent, fanfictions often explore the turmoil he felt between his loyalty to Voldemort as a Death Eater and his real allegiance to Dumbledore. Another theme is his relationships with other Death Eaters, like Bellatrix or Lucius.
Voldemort himself, of course, is the most prominent in a sense. But in the fanfiction, his relationship with the other Death Eaters could be different. He might be more distrustful or have different expectations of them. And then there's Barty Crouch Jr. He could be a major player in the fanfiction, with his skills in disguise and dark magic. His actions could drive some of the major plotlines in the fanfiction.
Bellatrix Lestrange is also a likely candidate. Her encounter with Hermione would be extremely intense. Given her loyalty to Voldemort and her rather unhinged nature, she would likely pose a serious threat to Hermione, but Hermione might also find a way to use Bellatrix's madness against her.
A fanfiction involving Hermione and Death Eaters could focus on a moral dilemma. For example, if Hermione has the chance to save a Death Eater's life, would she do it? This could explore her character's sense of right and wrong. It could also be about how she endures the psychological torture that the Death Eaters might inflict on her, showing her strength and resilience.
A possible motive could be self - preservation. If they believe that Voldemort's downfall is inevitable and that by saving Harry, they can gain some form of leniency from the side that opposes Voldemort. They might think that Harry has enough influence to spare their lives if they help him.
Well, in some fanfictions, Hermione might use her superior intellect. She could outwit the Death Eaters by setting up elaborate magical traps. For example, she could use transfiguration magic to create objects that suddenly turn into something dangerous when the Death Eaters approach. Another way could be through her extensive knowledge of potions. She might create a potion that incapacitates or kills them when they come into contact with it.