Don't deliver him. Use him to gain entrance to the Planar Sphere.
Delivering Valygar is considered to be an "evil" act...only do this if you are playing Evil and have an evil party. The cowled wizards are a bad, bad, bad lot...remember what happened to Imoen.
Go to the Planar Sphere with Valygar, and pretty soon, you'll understand just what kind of "fine" people the Cowled Ones are.
Cheers,
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