There could be Annabeth. She is Percy's close friend and often plays a crucial role in Percy's adventures. In a situation where Thor kneels to Percy, she might be there to witness it and offer her own thoughts or reactions.
One possible reason could be that Percy has shown some extraordinary power that even Thor, a powerful god, respects. Maybe Percy has defeated a common enemy in a really remarkable way that makes Thor recognize his strength and kneel in admiration.
The 'fish - out - of - water' trope is also seen a lot. When Percy ends up in Thor's world or vice versa, they are both out of their element. Percy has to deal with the strange Norse landscapes and customs, while Thor might struggle with the modern - day world if he goes to Percy's. It creates a lot of comical and interesting situations in the fanfiction.
One great 'Percy Jackson Thor Fanfiction' is 'The Godly Alliance'. It combines the worlds of Percy Jackson and Thor in an exciting way. The author does a great job of mixing the different mythologies. Percy's skills blend well with Thor's godly powers, making for some really cool action scenes.
In the realm of fanfiction and crossovers, it can be considered normal. Fanfic often plays with different universes colliding, so Thor being interested in a Percy Jackson fanfic is just part of the creative and often wacky world of fan - created stories.
One great Percy Jackson Thor fanfic is 'The Gods' Alliance'. It combines the worlds of Percy Jackson and Thor in a really interesting way. The characters interact in a way that feels both true to their original personalities and also creates new and exciting storylines. Another one could be 'Percy and Thor: A Meeting of Heroes' which focuses on a chance encounter between Percy and Thor and how they deal with the differences in their powers and cultures.
A very creative 'Thor meets Percy Jackson' fanfiction involves the two being sent back in time to the creation of their respective mythologies. They have to make sure things happen as they should without changing history too much. It's full of interesting twists as they interact with the primordial beings of both mythologies.
Thor's ability to fly with his hammer could be enhanced by Percy's control over water. Percy could create a water - spout or a current of water in the air that Thor could ride on, increasing his speed and maneuverability. In turn, Thor could use his strength and lightning to protect Percy when he is using his water powers in a vulnerable state, like when he is concentrating on creating a large - scale water structure.
A plot could involve Percy being sent to retrieve Thor's hammer as a favor to the Norse gods. He'd have to face many challenges on his way to the hammer, like battling Norse monsters that are guarding it. Once he gets there, he might find that the hammer has a mind of its own and tests Percy to see if he's worthy. This could be a great way to show Percy's growth as a character, as he'd have to rely on his wits and not just his powers. And in the end, he might either return the hammer or keep it for a while to use against a greater threat in the Percy Jackson universe.
Perhaps a rogue member of the Thor Corps who has been corrupted by the power of a Greek artifact. This person would then try to use the combined powers of both worlds for their own evil purposes, creating conflict between Percy and the rest of the Thor Corps.