Another theme is how his relationships change. His friendship with Arthur could become more of an equal partnership in some fanfictions. Arthur might see Merlin in a new light, not just as someone to order around. And his relationships with the other knights also shift, as they now have to accept this new, more physically capable Merlin.
One common theme is self - discovery. When Merlin has muscles, he often has to re - evaluate his own identity and how he presents himself. For example, he might be seen as more of a warrior type, which is different from his traditional role as a servant and a secret sorcerer.
One common theme is power enhancement. With the added muscle, Naruto is often portrayed as having greater physical power, which can translate into more effective combat abilities. For instance, his taijutsu could be on a whole new level.
Power dynamics is also a theme. His muscles can give him an edge in physical confrontations, which changes the power balance in his interactions. For example, in some fanfics, it makes the Slytherins more wary of him, as they see him as a more formidable opponent.
One great 'Merlin has muscles' fanfiction is 'Muscular Merlin's Adventures' on FanFiction.net. It really focuses on how Merlin's newfound muscles change his dynamic with Arthur and the knights. It has some really interesting character interactions and a unique take on Merlin's character development.
One common theme is the reaction of others. Characters in the 'naruto' universe will react to Naruto's new muscular form. Some may be jealous, some may be inspired. Also, the training process is often a theme. How Naruto endures tough training regimens to achieve his muscular physique is detailed in many fanfictions. In addition, there's the theme of using his new - found strength in battles against various enemies, which showcases his growth as a character.
A common theme is power enhancement. Danny's new muscles often come with increased power, which he has to learn to control.
One common theme is the clash of different magical systems. Merlin has his druidic magic and Loki has his Asgardian magic, so a lot of fanfics explore how these two types of magic interact. For example, in some stories, they might try to combine their powers to defeat a common enemy.
In sub Merlin fanfiction, a major theme is secrecy. Given Merlin's sub position, he must keep his magic a secret, and this secrecy drives a lot of the plot. Another theme is growth. He grows as a person and as a magic - user while being in a sub role. It's about how he overcomes the limitations of his position. Additionally, the theme of sacrifice is common. Merlin is often in situations where, because of his sub role, he has to sacrifice something for the greater good, whether it's his own safety or his relationships.
The theme of sacrifice is also quite prevalent. In many fanfictions, Merlin's father has made sacrifices for Merlin's future, which Merlin discovers as the story progresses. It gives a deeper understanding of their relationship.
In Merlin vampire fanfiction, the theme of acceptance is quite common. Whether it's Merlin accepting the existence of vampires or the vampires accepting Merlin's power. Another is the theme of transformation. Merlin might transform in some way due to his encounters with vampires, or the vampires themselves may transform, either physically or in their attitudes. And the theme of forbidden knowledge often pops up, as the vampires may possess knowledge that is both dangerous and alluring to Merlin.
Another theme is friendship. The neckerchief can be a focal point for the relationships Merlin has with Arthur, Gwen, and the other characters. For example, it might be a gift from a friend that holds special meaning.