Hopefully nopantsyet will read this. I would offer you a word of caution against applying XP in this way. If you have some smart metagamer players, they will be able to figure out if they are going to face an enemy again based on the XP you give them.
As a player, I think it would suck to battle a high level spellcaster every so often and get no XP for it if he got away. While you based your decision on how he influenced the fight with his minions, which is fine, you need to ask yourself how much XP you are willing to give if the PCs confronted the villian alone.
What I am trying to say is that if the PCs somehow caught the villian by himself, beat up on him, but he teleported away, how much would the PCs get for him alone?
Since there is "double jeopardy", they would get none. I offer my opinion that they should get half--if they are going to face him again. Of course now that they are aware of his teleportation abilities, they should be able to kill him if they can get a Dimensional Anchor spell to affect him. You are the DM, you make the call.
As a player, I think it would suck to battle a high level spellcaster every so often and get no XP for it if he got away. While you based your decision on how he influenced the fight with his minions, which is fine, you need to ask yourself how much XP you are willing to give if the PCs confronted the villian alone.
What I am trying to say is that if the PCs somehow caught the villian by himself, beat up on him, but he teleported away, how much would the PCs get for him alone?
Since there is "double jeopardy", they would get none. I offer my opinion that they should get half--if they are going to face him again. Of course now that they are aware of his teleportation abilities, they should be able to kill him if they can get a Dimensional Anchor spell to affect him. You are the DM, you make the call.