Friendship is a very common theme. Their bond is often explored, like how they trust each other unconditionally. For example, in many fanfictions, Gwaine will always have Merlin's back in dangerous situations.
Loyalty is also a prevalent theme. It shows how they remain loyal to each other and to Camelot. In some fanfictions, their loyalty is tested, but they always come out stronger in the end. For instance, when Merlin's magic is discovered by some in Camelot who want to harm him, Gwaine stands by him.
Adventure is another common theme. Since they are both characters from a world full of magic and quests, fanfictions usually send them on various adventures. They might be fighting evil sorcerers or searching for lost artifacts.
Another theme is loyalty. They are loyal to Camelot and to each other. In many stories, this loyalty is tested, for example, when they have to choose between following the rules of Camelot and doing what they think is right. It makes for some really interesting plotlines. And often, there's also the theme of adventure. They might go on quests, fight monsters, or discover new magical things, which adds a lot of excitement to the stories.
One common theme is friendship. Since Gwaine and Merlin are already friends in the original series, the OC often comes in to either strengthen their friendship or create some sort of conflict within it. For example, an OC might be jealous of their bond at first.
One common theme is loyalty. Gwaine is always shown to be loyal to Merlin, no matter what. Another theme is adventure. They often go on adventures together, which strengthens their bond. Also, trust is a big theme. Merlin trusts Gwaine with some of his secrets, and Gwaine respects that trust.
Friendship is a very common theme. They often start as acquaintances and grow into very close friends. Another theme is adventure, as they usually go on quests or face some sort of danger together.
Some fanfics may focus on the concept of female empowerment. The female Merlin could be portrayed as a stronger or more assertive character compared to her male counterpart. Gwaine might be inspired by her strength and they could team up to fight against injustice or magical threats in Camelot. This gives a new spin on the traditional Arthurian legends.
Love and loyalty are always big themes. Their deep love for each other is explored, how they stay loyal through thick and thin. In some fanfictions, there's a theme of sacrifice, where one of them might be willing to sacrifice something important for the other's well - being. And cultural differences between them can also be a theme, as they come from different backgrounds, and how they bridge those gaps in their relationship.
Well, there could be themes of responsibility. With Merlin being pregnant, Gwaine would have to step up and take on new responsibilities. There might also be a theme of facing society's reactions. If this is set in the Merlin universe, the medieval - like society might have strong opinions about an unmarried pregnancy. Additionally, there could be a theme of friendship being tested, as their friends might react in different ways to this situation.
Well, in fanfiction, Merlin and Gwaine's friendship is really cool. Gwaine is the kind of friend who's always up for an adventure with Merlin. He's not afraid to get into trouble right beside him. They have a great dynamic where Gwaine can be a bit more carefree and Merlin is sometimes more cautious, but they balance each other out. Their friendship also gives Merlin someone he can really trust outside of Arthur. Gwaine doesn't judge Merlin for his secrets and is always there to have his back, which is a really important aspect of their relationship in the fanfictions.
A good Gwaine and Merlin friendship fanfiction should have strong characterizations. It needs to capture Gwaine's roguish charm and his loyalty, as well as Merlin's kind heart and the burden of his secret magic. For example, if Gwaine is written out of character as being too serious all the time, it won't feel right.
Character development within the context of the kiss is a great element too. After the kiss, how do they change? Do they become more confident in their relationship? Or do they face challenges because of it? Some fanfictions might show how Merlin, who is often cautious, becomes more bold in his feelings for Gwaine after the kiss. And Gwaine, who is usually carefree, might start to think more about the future with Merlin. All these elements combined can make a Merlin and Gwaine kiss fanfiction really engaging.