They could start with a formal greeting. Given the history between Elves and Dwarves, they would be polite but reserved.
In fanfiction, their interaction could be complex. At first, there might be some cultural misunderstandings. For example, the Dwarves' love for mining and underground living could seem odd to the Elves. But as they get to know each other better, they could find common interests. Maybe they both love a good adventure and would embark on a journey together to explore an ancient ruin. Elladan and Elrohir's elven skills, like archery and stealth, could complement the Dwarves' strength and combat skills. This would create a great dynamic between them and lead to an interesting story.
In the fanfiction, perhaps Elladan and Elrohir would be intrigued by the Dwarves' craftsmanship. The Dwarves, in turn, might be impressed by the Elves' grace and magic. They could end up sharing stories around a campfire, forging an unlikely friendship.
One common theme is friendship. Since the original characters (OCs) are often inserted into the world with Elladan and Elrohir, the development of friendship between them is a big part. For example, the OC might start as a stranger and gradually become a trusted ally.
One interesting story could be about their early adventures in the forest near Rivendell. Maybe they discover a hidden glade filled with magical creatures. Another could be about their first attempts at learning elvish archery from their father, Elrond.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are often many Tolkien - related fanfictions there, and you can specifically search for ones about Elladan and Elrohir as babies. Another place could be some Tolkien - focused forums, where fans might share their own written works or recommend good fanfictions.
Another interesting one is 'Among the Elves: Elladan, Elrohir and OC'. This story dives deep into the elven culture and how the OC adapts to it while being in the company of Elladan and Elrohir. It shows their daily lives, their training, and how they interact with other elves. The descriptions of the elven settings are really vivid, making you feel like you're right there in Middle - earth.
He would probably try to reason with the dwarves. Legolas is not one to jump into a fight immediately. He might try to explain that there is no need for such hostility and that elves and dwarves can resolve their differences in a more civilized way. If reasoning fails, he would then start to look for ways to break free from his bonds and overpower his captors using his elvish agility and archery skills.
Naruto would probably be very cautious around Aizen at first. He's used to facing powerful enemies, but Aizen's deceptive nature would be a new challenge. Aizen, on the other hand, might see Naruto as an interesting specimen, someone with a strong will and great power that he could potentially manipulate.
Naruto would probably be very curious about the succubus. He might start by asking a lot of questions. He's not one to be easily intimidated, so he'd likely approach her without much fear.
Naruto would probably be very curious about Gandalf. He'd be asking a million questions about Gandalf's staff, his magic, and his long beard. Gandalf, on the other hand, might be intrigued by Naruto's determination and the strange power of chakra. He could see Naruto as a being with great potential for good in a world full of darkness, just like Frodo in Middle - earth.
Snape would probably start off being rather aloof. He'd observe the Avengers' behavior and abilities before making any real moves to interact. He could be sarcastic towards them, especially if they make assumptions about him or his magic. But as time goes on, he might start to see their value and open up a bit more, sharing some of his magical knowledge.