High Priest

 is a boss found in the Hollow.

Behavior
The High Priest drifts towards the player, occasionally dashing in a random direction. Additionally, bullets that travel along waves randomly appear from the walls. The High Priest has several attacks:
 * Surrounds himself with a ring of large bullets, fires homing skulls that burst into 6 bullets when destroyed, then fires the ring of bullets outwards.
 * Darkens the room, teleporting around and firing waves of projectiles from random locations.
 * Extends both arms and sprays rotating streams of bullets.
 * Extends both arms and sprays bullets randomly in all directions.
 * Fires wide spreads of triangular bullets.
 * Fires a single, fast bullet that homes in on the player.

Tips

 * The homing skulls can be taken down by a weapon with a high attack speed and low reload time. They can also be destroyed by simply leading them into a wall.
 * When the room darkens, the waves of projectiles can easily be dodged by staying in a corner and dodge rolling into the corner whenever a wave approaches.
 * The High Priest can be hit by Blasphemy and Bullet Bore while performing his disappearing attack and can be killed this way, unlike Cannonbalrog.
 * Using Potion of Lead Skin on their rotating attack does extreme damage.

Trivia

 * High Priest's appearance and behavior are references to the Dark Bishop, an enemy from Hexen.
 * High Priest's artwork is a reference to Ningauble of the Seven Eyes from Fafhrd & The Gray Mouser.
 * High Priest and Cannonbalrog can both die of poison and fire during their invulnerable attacks.
 * High Priest is the default sprite for bosses.
 * The entrance to High Priest’s boss room is always from below, despite the arena not having any restrictive elements like Wallmonger or Bullet King.
 * The High Priest is significantly rarer than the other two bosses of the Hollow.
 * A picture of the High Priest pulling of his hood can be seen in Abbey Of The True Gun.
 * High Priest's pistol head bears some resemblance to the heads of Gun Slave Units from the manga series No Guns Life.