The daelkyr that was bound under the earth at this location has been able to escape a small amount of it's essence and has bound itself to you. Your alignment has now moved from Neutral Good to True Neutral (with evil tendencies) as the daelkyr (the voice) is now a part of you. You can still decide how you want to roleplay Jango as he continues on, but just like an intelligent magic weapon can assert a certain amount of power over the situation, so can this fiend. And if you act in ways the daelkyr does not like, you may occasionally find your actions overruled.