Bring the Tablet of Sael'hai to Archmage Xylem in Azshara.
This final tablet goes to someone very dangerous, [player]. Heed me when I tell you that I trust this person far less than anyone else I've asked you to meet with.
Archmage Xylem has a tower up in the hills overlooking Azshara. He's human, but he acts like no human I've met... or killed. He exudes power, and I dare not ask him what he plans on doing with the tablet.
He came to me, but told me that his bodyguard Sanath would help me get to the tower when I was ready to meet him. Look north for Sanath.