In control of all the keys to the vaults under the Bank of Lesbon is the Keymaster; a pale, agoraphobic freak. Obsessed with keys he had all the vault keys attached to his body as piercings. His employers did not like this as it meant they could not fire him without painfully torturing him to remove the keys.
The Keymaster was one of the casualties during the 638 heist. His body was found with two guards outside an empty vault. Keys were strewn all over the room and it seems many of them had been torn off his body. He clearly died in agony.