Maybe there's a plot where they have a secret wedding ceremony in a magical place, like a hidden grove in the forest that only Merlin knows about. And then they have to deal with the implications of being married while still maintaining their public personas in Camelot.
One plot idea could be that they have to overcome the initial shock and resistance from the kingdom. Since it's an unconventional relationship in their world, they face challenges from the court, nobles, and even some of the common folk. But through their unwavering love and some heroic deeds, they gradually win people over. Another idea is that a magical curse forces them to get married to break it, and in the process, they discover their true feelings for each other.
Fanfiction.net is also a good place to look. A lot of Merlin - Arthur related fanfics are posted there. However, the search function might not be as advanced as AO3. So, you might need to browse through different categories related to the Merlin fandom to find the ones about their secret marriage.
There might be. Fanfiction often explores different and unique storylines that the original show or story may not have delved into. In the case of Merlin secretly marrying, it could be a way to add a new layer of drama and intrigue. Maybe he marries a commoner secretly, defying the class differences in Camelot, and they have to keep it a secret to protect their relationship from the wrath of the nobility.
Their wedding would be a grand affair. It might be held in Camelot's grand hall, filled with knights, nobles, and common folk alike. Arthur would surely wear his finest armor, polished to a shine, while Merlin would don a simple yet elegant robe. There would be feasting for days, with music and dancing. The vows they exchange would be a blend of the traditional and the deeply personal, pledging their love and loyalty to each other in front of all their friends and subjects.
One interesting plot point could be the reactions of their Pokémon. For example, Pikachu might be a bit jealous at first because Ash is spending so much time with Cynthia. Another plot point could be the cultural differences between Kanto (where Ash is from) and Sinnoh (Cynthia's region). They could incorporate elements from both cultures into the wedding. Also, a plot point could be the challenges they face before the wedding, like an evil team trying to disrupt the event because they fear the power of their combined Pokémon knowledge and skills.
In a fanfiction about their wedding, a plot point could be a mix - up with the wedding dresses. Jessie ordered a specific one but gets a completely different design. She has to decide whether to go with it or try to find the original in a very short time. Another interesting aspect could be the bachelor and bachelorette parties. Maybe something crazy happens at Luke's bachelor party that makes Jessie a bit worried at first, but then she realizes it was all in good fun. And there could be a moment during the ceremony where the officiant forgets the words, leading to a humorous and heartwarming moment.
One interesting plot point could be the reactions of their friends and allies. How would the members of the Occult Research Club respond? Another could be the challenges they face in planning a wedding that suits both their demon and human - influenced cultures. For example, they might have to deal with traditional demon wedding customs that Issei is not familiar with.
One way they overcome challenges is by being true to themselves. Arthur, as the king, has to balance his duties to the kingdom with his love for Merlin. He realizes that his love for Merlin doesn't make him a weaker king but a more compassionate one. Merlin, on the other hand, uses his magic not just to protect Arthur but also to show the people of Camelot that he is an asset to the kingdom. Together, they face any rumors or negative talk head - on, and their love for each other only grows stronger through these difficulties.
One idea could be that in a moment of extreme danger, Merlin and Arthur share a kiss as a way of saying goodbye, not realizing they'll both survive. It could be a spur - of - the - moment, passionate kiss that catches them both by surprise. Later, they have to deal with the newfound feelings this kiss has unearthed.
Yes, there are likely fanfictions on this topic. The 'Fairy Tail' fandom is quite large and creative, so it's not uncommon for fans to write about such pairings getting married in secret. However, the availability might depend on the specific fanfiction platforms you search on.