User blog comment:Rod12/Lancelot use in Series 4 and His Possible use in Series 5/@comment-3012002-20120212040816/@comment-4190137-20120212051611

I think he could also appear to Arthur on the brink of death (after Mordred defeats him) and tell him to be strong and explain that he was a shade when he kissed Gwen. And if that happens I think Uther and Ygraine could appear as well. Another way is that someone finds the bracelet Gwen through away and fall in love with Lancelot, which could lead to footage of Lancelot being shown, whether if it's a resurrection of a vision of the bracelet holder kissing Lancelot or something. He could rise out of the Lake of Avalon and give Merlin something important just like Freya did. And they could also show archive footage of him kissing Gwen. They are a few of my theories to how he could return.