Often, there's a plotline where Loki has some inside knowledge about an enemy that the Avengers are facing. Maybe he has some past connection with the villain. So, he becomes a key source of information. There could also be a plot where Loki's presence in the Avengers causes some internal conflict within the team. Some members don't trust him, while others see his potential. This conflict and how it's resolved is a common plotline too. And sometimes, Loki might get kidnapped or held hostage by the enemy because of his new - found alliance with the Avengers, and the team has to rescue him.
In Loki helps the Avengers fanfiction, his character development can be quite complex. At first, he may be reluctantly helping the Avengers due to some self - serving reason, like getting out of a worse situation or trying to prove something to himself or others. But as time goes on, he witnesses the Avengers' values up close. Their selflessness, courage, and determination might start to rub off on him. He could then actively choose to be a part of the team, not just for his own gain, but because he truly believes in their cause. His development might also involve learning about emotions like friendship and trust, which are new concepts for him, especially in the context of the Avengers.
Thor would be a likely candidate. Since he is Loki's brother, he already has a connection with him. Thor might be the one to convince the other Avengers to give Loki a chance and be the first to reach out and try to befriend him in this new situation.
He would probably interact a lot with Thor. Since they are brothers, there is a pre - existing relationship full of complexity. Also, he might interact with Iron Man quite often. Tony Stark's sarcastic nature and Loki's trickery could lead to some really interesting exchanges, either in the form of verbal sparring or working together on some high - tech and magic - combined projects.
In Avengers fanfiction, Loki and Sigyn can be depicted in various ways. One could have Sigyn as a force for Loki's redemption within the Avengers' universe. She might use her connection to Loki to try and sway him from his more villainous tendencies, adding an interesting dynamic to the Avengers' storylines.
Loki could also provide the Avengers with valuable information about otherworldly threats. Since he has connections to different realms, he may know about an upcoming invasion. In return for his help, he could demand that the Avengers clear his name for some of his past misdeeds, leading to an interesting dynamic between them in the fanfiction.
One idea could be that Loki gets turned into a vampire while in the midst of his schemes against the Avengers. This new state gives him different powers and motives. He might struggle with his newfound thirst and also use his vampire abilities to outwit the Avengers in different ways.
If Loki impersonated Thor, the real Thor would be furious when he found out. The other Avengers, like Iron Man, might initially be confused but then quickly realize something is off. Iron Man would likely use his technology to detect the impostor. Hulk might just smash first and ask questions later when he senses something wrong with 'Thor'.
Maybe the Avengers are trying to prevent a powerful artifact from being misused. Loki, who has a history with artifacts, offers his assistance. He might do this to gain some sort of favor from the Avengers or because he realizes the consequences of the artifact falling into the wrong hands. In the fanfiction, he could use his trickery to steal the artifact back from the villains before they can use it.