Eleazar, Silenced Hierophant is encountered in the third act of Wolcen Lords of Mayhem.
You encounter Eleazar, Silenced Hierophant during Illusions of Peace quest. This page has information about his attacks and the most effective strategies.
The boss has a shield in front of him. You must jump inside to deal damage. Otherwise, all your attacks will bounce off the shield.
The boss's main attack is a hail of arrows. However, they are easy to dodge - the game informs you where the arrows will land.
Eleazar isn't difficult to beat. Remember that you just need to stay close to be sure that every attack hits the target.