Glavin -- brief version

Glavin, Arm to Heimdal is a planetar who originally came to Sigil as a proxy from The Heroic Domains of Ysgard. Now, however, he is a Fated or more specifically he is the leader of the Teesh.
Glavin is first presented to the characters in Act 2: Information from Glavin. It is he that gives the characters their first clues of what is going on here. He also effectively gives the characters their outpost, Kateesh House across the street from the Hall of Records . He also gives them a lead to go see Lothar the Old -- Master of Bones to make their escape out of Sigil and to start their quest.

Glavin, a Fated, leader of the Teesh