A group of dark elves could be the antagonists. They are seeking a powerful artifact that Donald Blake has unknowingly in his possession. Thor gets involved when he realizes the elves' plan could not only harm Blake but also have far - reaching consequences for Asgard. The elves use their dark magic and cunning to try and outwit Thor and Blake throughout the fanfiction.
The plot might involve Thor being banished to a dimension similar to Earth where Donald Blake lives. At first, Thor's brash Asgardian ways clash with Blake's more reserved and scientific approach. But as they get to know each other, they find common ground. For example, they both care about the innocent. They then discover that a dark entity is trying to open portals between their two worlds to cause chaos. So, they must combine Thor's strength and Blake's intellect to stop this threat and in the process, become great friends.
One can anticipate some epic battles or challenges. Maybe they have to rescue a group of people trapped by a powerful sorcerer. During this, Thor would use his hammer and lightning powers, while Donald would use his wits and whatever resources he can find in his rather strange world. Their combined efforts would be a sight to behold.
It could be an amazing story where Thor's Asgardian strength and power meet Donald's rather comical and often bumbling nature. Maybe they team up to face a common enemy, like a villain who has invaded both their worlds.
Another antagonist could be a powerful frost giant. If Percy is involved in protecting Asgardian interests related to Thor, a frost giant could be a major foe. They are strong and have their own motives for opposing Thor and his champion. They might see Percy as an easy target at first but soon realize his strength.
It could be Cinder Fall. She's always been a major villain in RWBY. She might be the one who arranges for Blake and Jaune to be banished as part of her evil plan to gain more power or cause chaos in the world of Remnant.
Perhaps an evil organization that wants to use the power of both Naruto and Blake for their own malicious purposes. They could be from a parallel dimension where they have studied both Naruto's world and RWBY's world. They would try to capture Naruto and Blake, forcing them to fight not only for their own freedom but also to protect the two universes from the organization's evil plans.
Well, perhaps Thor and Richard could meet in a modern city. Thor is on a mission to retrieve a powerful artifact that has been smuggled into the human world. Richard, who is an expert in ancient relics, unknowingly has the key to finding this artifact. Their meeting could start with Thor saving Richard from some thugs who are after the same artifact. And then they team up to find the item before it falls into the wrong hands.
Richard could be an ordinary human being. Just a regular guy going about his daily life until he has an unexpected encounter with Thor. Maybe he works in a coffee shop and Thor stumbles in while chasing a villain.
Well, perhaps Percy would initially mistake Thor for a new kind of demigod. Thor, on the other hand, would be intrigued by Percy's unique skills. They could exchange stories about their adventures. Percy would tell Thor about his quests in the Greek world, and Thor would share his tales of Asgard. And in the end, they might become friends and even learn new combat techniques from each other.
One key element is the cultural clash. Nico comes from a different mythological background compared to Thor. Their different beliefs, powers, and ways of doing things often lead to interesting situations in the story.