The Old Man and the Lake (джен)

For a KMM prompt: http://kinkme-merlin.livejournal.com/34275.html?thread=36189923#t36189923
What I want is for a folklore to start slowly growing surrounding Merlin waiting by the lake. [...] People talk about him as a ghost story, and variants crop up, like that he's waiting for a drowned lover, or he's waiting for a brother who promised to meet him there. Eventually, no one seriously believes that there's some man who always comes to wait by the lakeside, that the same man has been doing so for thousands of years. Even if he comes still.