Professor Nakayama is the primary antagonist of Sir Hammerlock's Big Game Hunt. He is a small, wiry man with a multitude of Eridium fragments protruding from his skin, and has enhanced himself further by grafting on a robotic weapon appendage protruding from his back and over his right shoulder.
Nakayama is a scientist who had become distraught after the death of his idol, Handsome Jack. Through further misfortune, a Hyperion transport ship that he was on crashed on the primitive continent of Aegrus, leaving Nakayama to fend for himself in hostile territory. To that end he resumed the kind of experimentation that he had done for Hyperion, grotesquely modifying both himself and some of the local fauna. Very soon he seized on a plan to clone his idol, Handsome Jack.
His obsession with Jack began sometime before the events of Borderlands: The Pre-Sequel. The exact reason for his obsession is unclear.
Sometime during the events of Borderlands: The Pre-Sequel, Nakayama was captured by Lost Legion soldiers and imprisoned. When he learns of Jack's Vault Hunters' return to Helios, he issues a plea for help. After being freed, he begins offering missions, primarily concerning his attempts to woo his idol. Later, during the mission Lab 19, he offers additional commentary about his experiments regarding the Tiny Destroyer.
During the events of Sir Hammerlock's Big Game Hunt, Nakayama is soon alerted to the presence of the Vault Hunters and makes threats about how he will exact his revenge for their killing of Handsome Jack. Rather than face them however, he sets a few obstacles in their path, but becomes increasingly agitated and fearful as these are swept away. Only at the very end does he fully reveal himself, but before he can do anything more, he suffers an ignominious fate when he trips on some stairs and falls to his death.
Sometime after his death, his corpse was recovered by Shade and was put up for display at the World of Curiosities. During a visit to the antique shop by Rhys and Vaughn, Rhys recognizes Nakayama and takes his ID drive, still hanging onto his shoulder cannon. Rhys later uses the ID drive in an attempt to track the money he lost, but fails and blacks out. It is later revealed that the ID drive contained a Handsome Jack AI, which was downloaded onto Rhys' brain. After this, he began hearing Jack's voice, and occasionally saw Jack's image in hologram form.
- Nakayama is profoundly incompetent, as shown by his placement of precious DNA samples in insecure safes, and by his habit of unintentionally revealing his plans to his enemies in advance.
- After Nakayama appears, his health bar will be displayed at the top of the screen. However, before any combat takes place, he will lose his balance and tumble down the ramp, losing a portion of his health with each impact. This will continue until he reaches the bottom of the ramp, where he loses the last of his health and dies.
- In Borderlands: The Pre-Sequel, Nakayama reveals that his doctorate is actually in botany and that he posed as a geneticist in order to work with Jack.
- Nakayama mentions that he poisoned the CEO of the Atlas corporation during his first encounter with the Vault Hunters, because neither they, nor Sir Hammerlock, knew who he was.