Encountered only in the Grave of Saints, which they have infested and now call home. Corpse Rats will appear from tombs and holes in the ceiling, usually in groups to attack the player. They are the initial hazard of the Royal Rat Vanguard boss fight.
One can avoid all of the rats with relative ease simply by rushing to the Grave Entrance bonfire located on the second floor. When the player is forced to engage them, they will want to avoid being attacked too much at one time, especially since taking hits from multiple rats will lead to Petrification and an instant death.
Old Radiant Lifegem