Yes, in some fanfictions, Merlin is written as Mordred's father. Writers often like to explore different family relationships and backstories in fanfiction, and this is one such interesting take on their relationship.
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.
Meeting his father could have made Merlin more confident. Knowing his family background and having his father's presence (even if it was just in the fanfiction) might have given him a sense of belonging. He could also become more powerful, as perhaps his father passed on some knowledge or power to him.
Power dynamics is a major theme. As Merlin is Uther's son, it affects his standing in Camelot, both in terms of political power and magical power. Also, redemption is a theme sometimes. Uther was not always kind to magic - users, and this relationship can lead to a path of redemption for him in some fanfictions.
One popular 'Uther Merlin father' fanfiction is 'The King's Secret Son'. It delves into the idea of Uther secretly being Merlin's father and how that changes the dynamic in Camelot. It has great character development and interesting plot twists.
Sure. 'The King's Father' is a great one. It delves deep into Merlin's father's backstory and his relationship with Merlin in a very interesting way. It shows how his father's past actions and decisions influenced Merlin's life.
Well, it could be Arthur in a more creative and alternative fanfiction. Their deep bond could be taken to a whole new level with this unexpected turn of events.
They could have adventures where they explore ancient magical places. Maybe they find a long - lost magical artifact that has the power to change the fate of Camelot. Merlin, with his knowledge, and Aithusa, with its dragon abilities, would be a formidable team in such quests.
The father's reaction varies. In a particular fanfiction I read, the father was first in disbelief. He couldn't believe that the young man in front of him was his son Merlin. Then, as Merlin showed some signs or told some stories that only his son would know, the father became overjoyed. He started to tell Merlin about their family history that Merlin didn't know before, which was a very emotional and bonding moment between them.