The Two Dragons was originally the final third of the massive story that I had decided to call The Steel Dragon. When I turned it into a series instead, The Two Dragons sat for a long time waiting. When I finally had finished and published all the other five books, I looked at the manuscript again. The story still worked, but there needed to be significant changes in the ending.
Senta had picked up a dragon egg in book 4 that I hadn’t originally counted on. I added that. The original manuscript had a very long epilog that detailed everything that happened to all the characters. Since it was going to be a series, I had to take that off. In its place I needed an ending. I had written a little bit about Senta arriving in Brechalon (originally thinking that this would be many years later), so I added it. As it turned out, it tied in well with The Sorceress and her Lovers.
By the way, I am still following the information about the characters in the original epilog.
There are actually three dragons in the story, so which two are the ones in the title? I kind of like mirroring The Lord of the Rings. In The Two Towers, there are many more than two towers, and Tolkien never explains which two are the title locations.