One possibility is that there could be a big misunderstanding at first. The Avengers, used to Loki's tricks, might assume his wife is also up to no good. However, she could prove them wrong by showing her true intentions. Maybe she's a healer and offers to help an injured Avenger, which starts to change their perception of her.
In a fanfiction, when the Avengers meet Loki's wife, it could be a catalyst for a new adventure. Loki's wife might bring a new quest or mission to their attention. For instance, she could know of a powerful artifact that is in danger of falling into the wrong hands. The Avengers and Loki's wife could then team up to protect it. Along the way, they would learn more about each other and form new relationships. The Avengers would see that Loki's family has more to them than just being related to their enemy.
Well, Loki could cause all sorts of chaos. He might try to undermine the Avengers from within. For example, he could pretend to be Iron Man and give false orders to the team, leading them into dangerous situations. Or he could pose as Captain America and spread doubt among the Avengers about their mission and each other.
In this fanfiction, Loki might finally start to see the good in the Avengers. He could be forced to team up with them against a common enemy, perhaps an even greater threat from another realm. This situation would put Loki in a position where he has to rely on the Avengers, leading to some interesting character dynamics and potential for growth for his character.
In this fanfiction, Loki might start to learn about teamwork. He could form unexpected friendships with the Avengers. For example, he might bond with Thor over their shared past in a new way, now that they are both part of the Avengers group. He could also use his trickery skills to help the Avengers in their battles against other villains.
Well, in such a fanfiction, there could be intense battles. The Avengers might initially be on the defensive against Loki's children. Maybe Loki's children would have unique powers that the Avengers have to figure out how to counter. For example, if one of them can manipulate minds, it would cause a lot of chaos within the Avengers' ranks.
Well, in such a fanfiction, there could be a lot of conflict. Maybe Loki's son has some sort of hidden power that the Avengers initially fear. But then they might realize he's not as bad as they thought and try to help him control his powers. Or perhaps Loki's son is on a mission to prove himself and the Avengers see him as a threat at first.
One possibility is that Loki could initially be a reluctant ally. He might have his own hidden motives, like using the Avengers to get closer to a powerful artifact or enemy. But as time goes on, he could start to actually care about the team. For example, in a battle against a common foe like Thanos, Loki could use his trickery to outwit the enemy, creating illusions to confuse Thanos' minions while the Avengers attack from another angle.
They might see events that shaped Loki into the mischievous and sometimes villainous character he is. For example, the discovery of his true heritage. This could make the Avengers more sympathetic towards Loki, or it could make them more cautious, seeing how his past traumas have influenced his actions. In fanfiction, there could be all sorts of creative interpretations of these past events that would surprise the Avengers.
The OC might find themselves in a really strange situation. Loki could be using the OC as a pawn in a bigger scheme against the Avengers. He might try to use the OC to get some valuable information or as a bargaining chip. The OC, on the other hand, could be trying to outwit Loki, using their own wits and any knowledge they have of the Avengers' world. It would be a battle of intelligence between the OC and Loki.
Well, in such a fanfiction, there could be a lot of conflict. The Avengers might initially see Loki in his Jotun form as an even greater threat. They could misunderstand his intentions. Maybe Thor would be in a difficult position, trying to convince his friends that Loki still has some good in him despite his different appearance.
Loki might be forced to tell the truth about his real intentions towards the Avengers all along. Maybe he reveals that he's actually a bit envious of their unity.