"And We'll Walk From This Darkroom For the Last Time..."

The May Queen.

As I Am. Arthur wants Gwen to marry him. Obviously this much innocence, sweetness, and love, can only mean bad stuff is going to go down.
The May Queen. Lance meets Gwen for the first time and falls hard. As Snowy points out, this song sounds like Arthur/Lance. It really, really does.
Kingsword. IT ARE NOT EXCALIBUR RILLY.
Lady of the Lake. Merlin meets Nimue and falls hard. And turns into a horse. To impress her...?
Exile. Lance still loves Gwen, just in case you've forgotten!
Prodigal Son. Morgause, on the other hand, has got it in for Arthur.
War Between Brothers. Ostensibly about Mordred, but also about everything else going to hell. DEAD PEOPLE EVERYWHERE.
Three Queens. Arthur is in love with Morgause. Also Guenever. Also possibly Igraine. Do we have issues? Eh, maybe.
Crashing Down. Mordred: *JAZZ HANDS* *ALSO ARTHUR SUCKS*
Tristan and Isolt. Their love is so totally doomed from the start.