Thor's perception of Loki would change drastically. Instead of seeing him as his mischievous but ultimately Asgardian brother, he would start to view Loki as an outsider, an enemy perhaps. This change in their relationship would affect Thor's self - confidence. He might become more hesitant in his actions, constantly wondering if he could have done something different to keep Loki in Asgard. Also, he would have to face the political implications within Asgard, as some might see Loki's stay in Jotunheim as a threat and put pressure on Thor to take action.
Perhaps Loki is forced to stay in Jotunheim. There could be a powerful spell or curse that binds him to the realm. This could lead to an interesting plot where Thor has to find a way to break the spell and rescue Loki. It would also give Loki a chance to explore his identity while being stuck there.
One consequence could be a shift in alliances. Without Loki leaving Jotunheim, the relationship between Asgard and Jotunheim would be far more complex. The Asgardians might view Loki as a traitor, which could lead to Thor being caught in the middle. He loves his brother but also has loyalty to his home. Loki, on Jotunheim, could start to build a new identity for himself. He might use his knowledge of Asgard to strengthen Jotunheim, making it a more formidable force in the Nine Realms. This could set off a chain of events that would change the entire power structure of the realms.
A plot development could be Loki forming an alliance with the Jotuns against a common enemy. This enemy could be a threat to both Jotunheim and Asgard. Loki, being in Jotunheim, has the opportunity to broker this alliance, which would surprise Thor and the other Asgardians when they find out.
There's 'Thor's Redemption in Loki's Arms'. In this story, Thor realizes his true feelings for Loki after a series of events that nearly tear Asgard apart. It's a tale full of emotion and character development.
Well, in many such fanfictions, the age difference often makes Loki more naive or inexperienced compared to Thor. This can lead to Thor taking on a protective role towards Loki. For example, Thor might shield Loki from dangerous situations or guide him in understanding the world around them.
Thor might initially go into denial. He can't believe that Loki is truly gone. He may hold Loki's body for a long time, as if waiting for him to come back to life. Then, he could become angry. Angry at the situation, at whoever or whatever caused Loki's death. Eventually, he may find solace in the memories of Loki. Remembering the good times they had together and using those memories to move forward.
When Thor is mean to Loki in fanfiction, it can lead to a downward spiral in their relationship. Loki, feeling constantly attacked, may lash out in more extreme ways. Thor, on the other hand, may double down on his meanness, believing it's the only way to deal with Loki. This can create a cycle of animosity where any love or brotherly bond they had is overshadowed by anger and distrust. For example, Loki could start to form alliances with Thor's enemies out of spite, and Thor would see this as confirmation of Loki's untrustworthiness, making the relationship even worse.
I really like 'A Different Path for Loki'. In this fanfiction, Loki is given a chance to redeem himself in a unique way. It's full of interesting plot twists and great dialogue between Thor and Loki. The author does a wonderful job of exploring Loki's psyche and his relationship with Thor against the backdrop of the Asgardian world.
If Loki survived in Infinity War fanfiction, it could have led to a very different outcome. He might have used his trickery to deceive Thanos in some way. Maybe he could have pretended to be on Thanos' side while actually working against him. This would have added an extra layer of intrigue to the story as the other characters would have been unsure of his true motives.
These fanfictions typically show their relationship as something that has to be hidden from the rest of Asgard. It adds an element of secrecy and danger. The relationship is also often portrayed as a way for both characters to find solace in a world that doesn't always understand them. Loki's cunning and Thor's power are intertwined in a way that makes their connection unique and captivating.