Head of the Church of Amaunator
His High Radiance is the self-proclaimed leader of all the churches of Lathander and Amaunator. He is distant and surrounds himself with members of the militant Order of the Aster, a group he lead before being promoted to leader of the faith.
There seems to be a lean toward the martial and away from the spiritual in the Church of Lathander and Amaunator, and Morningstar is a the center of it. Further, the usually decentralized church is becoming increasingly beholden to the Spires of Morning, a shift that no doubt has rankled the heads of churches in other major cities. However, Morningstar seems to have a wide range of valuable friends who helped him to, despite not ever living in Waterdeep, take the Sunrise Throne.
This may not be the real Alabaster, or he may be in league with Count Rampyr or Vell Sr.