Prie Dieu are altars at which the Penitent One can kneel to rest, refilling all health and flasks, but causing killed enemies to respawn. Also, the game is saved, so upon death, the Penitent One will respawn at the last visited Prie Dieu.
Additionally, Prie Dieu are the only time at which the Penitent One can change the hearts equipped in Mea Culpa.
Also, after donating 20,000 Tears of Atonement to the church in Albero, the appearence of the Prie Dieu changes, as they are risen above ground by three figures. Once this happens, the Penitent One is allowed to teleport between the various Prie Dieu. In addition, once the Mirabrás of the Return to Port prayer is obtained, the Penitent One will be free to return to the last visited Prie Dieu at any given time.