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.
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.
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.
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.
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.
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.
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.
Often, the age difference is used to create a sense of mystery around Loki. Since he's much younger, he may have powers or abilities that are not fully developed yet. This can drive the plot as the story may revolve around Loki discovering and mastering these powers, with Thor sometimes being a mentor or a hindrance depending on the situation.
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.
It could strengthen their bond. They now have a common responsibility to protect and guide their younger brother. For instance, Thor might take on a more fatherly role, teaching him about honor and courage, while Loki could teach him some of his sly ways to outwit enemies, but also warn him of the dangers of excessive trickery. Their relationship could become more complex as they balance their own differences while raising the younger brother.
In comics, Thor and Loki have a tumultuous bond. Loki constantly tries to outdo Thor and gain more power, while Thor tries to keep him in line. Despite their differences, there's an underlying connection that keeps them intertwined in the storylines.