The Possessed Priest is a sub-boss featured in the quest Icthlarin's Little Helper. He wears a Menaphite robe and attacks using Strike Spells.
When fighting him, it is beneficial to have armour that gives good magic protection such as leather, dragonhide or a mage robe; alternatively, the Protect from Magic prayer will prevent him from harming the player.
Fighting the possessed priest.
As a mage, he has substantial magic resistance, along with high defence bonuses against stab and crush attacks; low-level players are advised to kill him with either slash or ranged attacks.
Note: If you take too long to defeat him, the message "The priest seems to have recovered from the Devourer's spell" will appear, and you will have to exit the door and re-enter to face him again with full Hitpoints. (Beware—do not exit the door, or you'll have to start the whole process over again).
The player will receive one of the potions below at random.