Player Rank is a statistic found in Castlevania: Grimoire of Souls. It is increased over the course of gameplay through the completion of quests and other challenges. Raising one's Player Rank unlocks a variety of things, including equipment slots and new Trials. The player's current Ether is restored upon every rank up, and with every other level their Ether maximum is increased. The maximum attainable rank is 70.
Player Rank also determines the maximum strength of the player's equipment. When upgrading equipment, the level of any given item cannot exceed the player's current rank, no matter how many Enhancement Runes are used.