Actually, Pluto is the Roman name for the Greek god of the Underworld, Hades. As ruler of the Underworld, Hades is responsible for governing the souls of the dead and his cohorts; such as Charon, The Grays, and the watchdog of the underworld: Cerberus.
Indeed its limbus, The Kings Path to be exactly where yuou will face a Doomed NM, Ram NM, Tortoise NM, Dragon NM and Behemoth NM, the latter three being on the same par as King Behemoth, Fafnir and Aspid