High Prophet Moorabi is a 7/5 7-drop legendary Priest minion class card whose special ability synergizes particularly well with any Priest Raza the Chained, or Kazakus decks that already aren’t running any duplicates.
When played, he’ll give all spells in your hand and deck Lifesteal, so if you played your cards right, you’ll be practically unkillable. With him on the board, you'll get the best of both worlds -- damage and healing. To add to his power, he’s also a pretty decent damage dealer.
Some have criticized that this ability would be better as a Battlecry, and others have also pointed out that Lifesteal isn’t a great route for Priests to go down since a control Priest deck wouldn’t really see any really great Lifesteal returns with this card until the late-game where most high-damage minions would be able to outpace the amount of Lifesteal you can use to heal back up.