Another theme is the exploration of their different personalities. Arthur is usually more responsible and DW can be more carefree. Fanfictions play with this by putting them in situations where their personalities clash at first but then they find a way to complement each other. For instance, in a story where they are planning a party for their parents, their different approaches initially cause problems but in the end lead to a great celebration.
The 'Redemption' trope is also seen in some fanfictions. Maybe Arthur has made some mistakes in the past, and Merlin helps him to redeem himself. Or vice versa. It's a way to explore the characters' growth and development. And then there's the 'Battle Against Evil' trope where they fight side by side against dark forces, which really showcases their bond and loyalty.
I really like 'The Sword in the Stone' as a fanfiction - like take on Merlin and Arthur. It shows Merlin as this wise and mysterious figure guiding Arthur on his journey to become king. There are also some great interactions between the two characters that show the deep bond they share. You can find it in many libraries or online bookstores.
He could be overjoyed if he believes the child is his. He would see it as a continuation of his lineage and a sign of their love. He might start making plans for the child's future, like ensuring the best education and training in Camelot.
Maybe Prince Arthur is on a quest to find his true identity and he discovers that King Arthur is an important part of his past or future. They meet and King Arthur recognizes a great potential in Prince Arthur. He takes him under his wing and together they face a common enemy, like an evil sorcerer who is threatening Camelot. Along the way, Prince Arthur has to prove himself worthy to King Arthur and the knights of the Round Table.
The banter between Merlin and Arthur in fanfiction is really interesting. It can range from light - hearted jabs at each other's habits. Merlin might poke fun at Arthur's love for jousting and how he always gets a bit too competitive. Arthur could retort by mentioning Merlin's clumsy attempts at serving him. Their banter also reflects the underlying respect they have for each other despite their different social standings. It's like a friendly sparring that keeps their relationship dynamic.
One reason could be for the continuation of his dynasty. In the context of Camelot, having a son would mean there is an heir to the throne. It would ensure the stability and future of his kingdom. Without a son, there could be disputes and power struggles over who will succeed him.
They might start off with a bit of rivalry. After all, they both bear the name Arthur. But then, they would likely start to respect each other. King Arthur could be a mentor to Prince Arthur, teaching him about the ways of Camelot and the code of chivalry. Prince Arthur, in turn, could offer fresh perspectives, which might at first be met with some resistance from King Arthur, but eventually he would come to appreciate them.
One great 'arthur x dw arthur fanfiction' could be 'Arthur and DW's Unlikely Adventure'. It takes the characters on a journey through a magical forest where they have to solve puzzles together. This fic really plays on their unique relationship and the differences in their personalities.
In Arthur and Sadie fanfiction, their romance often develops in the rugged backdrop of the Wild West. It might start with a chance encounter during a dangerous mission. Maybe Arthur saves Sadie from some bandits, and from that moment, a spark is ignited between them. Their relationship could be filled with unspoken feelings at first, as both are tough individuals not used to showing vulnerability.