Perhaps Merlin tells a story about the magical creatures he has encountered. He could describe the beauty and mystery of the unicorns he has seen in the enchanted forest. He might talk about how gentle they were, and how their presence made the forest seem even more magical. He could also mention the dangerous creatures like the basilisks and how he managed to avoid their deadly stares.
Merlin could tell a story about his adventures with Arthur. He might recall the time they went on a quest to find a magical artifact. Along the way, they faced many challenges, like battling fierce creatures and solving tricky riddles. This story would highlight their friendship and how they relied on each other, even when they had their differences.
In Merlin fanfiction, Merlin might tell a story about his magic origins. Maybe he shares how he discovered his powers as a young boy in Ealdor. He could talk about the first time he made something extraordinary happen, like making a flower bloom in the dead of winter. This story would not only be about his powers but also about the fear and wonder he felt at that moment.