Father Reen is a priest and part of a group of Saradominists, along with Gideon Bede and Father Badden, who are keeping an eye on a very dangerous demon worshipper called Denath. Heeding Reen's request for help starts Shadow of the Storm quest nearby Al Kharid bank. During the quest, he is needed to help summon Agrith-Naar again. If you do not have Silverlight with you or in bank when you start Shadow of the Storm, he will return it to you for free. While he is seen at the end of the quest, he can no longer be found in-game upon its completion. Father Reen comes originally from Al Kharid.
Father Reen has a phobia of flying (particularly magic carpets) as seen in Shadow of the Storm; when he tells the player he wouldn't be caught dead on a magic carpet, claiming the magic could run out at any moment.