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.
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.
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 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.
Power and its consequences is another theme. The OC, if they have special powers, has to deal with how to use them. In some fanfictions, the OC might struggle with the temptation of using their power for personal gain or to change the course of Camelot's history in a way that could have unforeseen negative consequences.
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.
Another one is 'Gwaine's Secret Encounter'. In this fanfiction, an OC stumbles upon Gwaine during one of his secret missions. The OC is a strong - willed character, and the way they interact with Gwaine and later Merlin is really interesting. The story delves into the backstories of the characters and how they all come together to face a common enemy. It's quite long but definitely worth the read as it has a lot of character development.
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.