The Ruin Sentinels can be found in The Lost Bastille past a large group of Royal Swordsmen. The boss fight is a three on one, unless the player stays on the ledge upon entering. This way, the player can challenge one sentinel at the beginning. After its death or the player drops to the floor, the other two sentinels will join the fight.
The summon sign of Pilgrim Bellclaire, an NPC white phantom, can be found in a cell in the hallway before the fog gate.
The Ruin Sentinels reappear as standard enemies in Drangleic Castle behind several doors in a wide open area, with spear-wielding Stone Soldiers guarding each and every door. Within here, there are a total of five Ruin Sentinels.