Grav'iton is fought as a Notorious Monster in Final Fantasy XI: Rise of the Zilart. An ancient Kuluu, she has been bound into the form of a Tonberry. She is fought alongside Tungs'iton and Molyb'iton in Zilart Mission 4: The Temple of Uggalepih.
In addition to her standard Tonberry abilities, Grav'iton can also use Everyone's Rancor at 25% health, a powered up version of Everyone's Grudge which deals damage equal to 50 times the amount of tonberries killed by the player. This makes it vital for the player to complete a sidequest to reset their "tonberry hate" to zero, otherwise it is very likely they will be killed by Everyone's Rancor.