Board Thread:Rewatching "Merlin" - Season One/@comment-5102537-20130330123307/@comment-5674726-20130403054607

''I do wonder, when regarding the fact that the Sidhe possessed princess Elena so that she can marry Arthur and give the Sidhe the opportunity to have one of them inside the walls of Camelot, why they tried or agreed to get Arthur's soul. If Arthur had died, their plan they had made 20 or so years ago wouldn't have worked. Why did they want one of them being in Camelot anyway? The only expanation would be that Elena was born during or after the Great Purge and the Sidhe wanted revenge. However, making a plan that would take decades until it works seems to be a bit unlikely, given that during that time thousands of people/sorcerers might die and by that strenghten Camelot when slowly erasing magic.''

Maybe, as an immortal race who weren't actually being killed off during the Purge, the Sidhe were playing the long game. What would twenty years be to the life of an immortal?

Depending on how the sacrifice worked, they could have intended to send a false Arthur back to Camelot so that they would control the kingdom through him. Since they would then no longer need Princess Elena in Camelot, she could have married another prince or King, giving them control of a second kingdom.