|Japanese VA||Junpei Asashina|
|English VA||Leraldo Anzaldua|
"It's sad. It's the same philosophy as the organization: 'As long as I'm fine, nothing else matters.' That's why this world is so insane." — Tsuneaki Iida
Tsuneaki Iida (飯田 恒明 Īda Tsuneaki) is a programmer working at Tyrannos Japan and is also heavily involved in the development of the real-life Btooom! game. He is also known among the employees involved in the Btooom! project to be in charge of game balance.
Tsuneaki has a long face and is often seen sporting a weary look, which is most notable due the wrinkles and dark-colored areas around his eyes. These characteristics are mostly attributed by sleep deprivation as a result of his long working periods. He is usually seen dressed in typical salaryman attire and has, during his visit to the island for server maintenance, been seen carrying a laptop via hand strap and a black leather bag with a shoulder strap, presumably for storage of the laptop, while moving. His hair sports a dark-colored brown to it and is also kept in small spikes protruding upright.
In certain occasions, such as his visit to the island, he can also be seen carrying a pistol, presumably for protection from hostile players and lizards.
At first, Tsuneaki can easily be seen as a supporter of the Btooom! project, especially when he is seen many times over spectating the actions of the Btooom! players without comment, but this later is proven to not be the case. Despite Tsuneaki's composed face, behind it hides a person who is often concerned as to whether Tyrannos Japan's involvement in the Btooom! project is justified in a humane stance. He has also been shown to be compassionate and encouraging to those he associates himself with, which is especially the case for Ryōta Sakamoto given the history that the two share.
Before the events of the island, he was known for having a friendly relationship with Ryōta and was often looked up to by the boy himself. Their relationship can generally be taken in as the dealings between a senpai and kōhai, with Tsuneaki as the senpai and Ryōta as the kōhai. This relationship is better known when Ryōta congratulates Tsuneaki upon getting accepted as a programmer to Tyrannos Japan along with other people, presumably friends. As a result of Tsuneaki's new job, Ryōta becomes further inspired to follow in Tsuneaki's footsteps. Although later on, during an interview with Ryōta, he informs Ryōta that there are not many openings in the company, thus crushing any hopes for the boy.
During the night of the 3rd day on the island, Tsuneaki is seen spectating Ryōta's group through a computer in the Tyrannos Japan company building just as Gemu Shusaisha walks in, bringing food in with him. The two then discuss on Ryōta's current situation, with Tsuneaki commenting on Ryōta's ability of coming into contact with four other people, making two of these four into his companions (Kiyoshi Taira and Himiko), and killing at least one out of the four (Yoshiaki Imagawa). They then proceed to conclude that a good amount of data can be extracted from Ryōta as he is one of the rare types to adapt themselves to the island rather quickly. 
It isn't until the night of the 3rd day on the island that Tsuneaki makes another appearance, this time presenting data collected from Hidemi Kinoshita to the president of Tyrannos Japan alongside Gemu. Tsuneaki then proceeds to tell of how spectating the players is possible by using realistic three-dimensional images that correspond with the IC chips capturing the movements made by the players implanted with them. With the developments now shown, the president then instructs the two to proceed as they had before. Later on during the 4th day, Tsuneaki is seen observing the battle between Ryōta and Nobutaka Oda from Ryōta's view on his computer, and though his fellow employees comment on the battle itself, Tsuneaki does not participate. 
Time passes. As a result of keeping up with the demands of the clients, a server malfunction occurs, rendering the abilities of the IC chips useless during the 4th night on the island. Having realized this, Tsuneaki claims full responsibility of the situation to Gemu and informs him that in order to remedy the crisis, he, along with Iwamoto, must personally visit the island itself to perform a server maintenance. Making haste, the two then board a helicopter and head over to the island. Although as they do so, it is revealed through the thoughts of Tsuneaki that he purposefully overloaded the servers, though his reason for doing so is unstated. Once they arrive on the island, Tsuneaki leaves Iwamoto to replace the overheated circuit boards, stating to the man that he'll check the power plant to assure him whether or not it was in working condition. As time passes, Tsuneaki manages to track down Ryōta and Himiko. And as he nears their location, he activates the safety locks on all their BIM. He eventually encounters the two, catching them by surprise. Tsuneaki proceeds to quickly tell them to not repeat anything related to their encounter, and enforces this with the display of his pistol's firepower. He soon explains to them that this survival game they've been forced to participate in is indeed being run by the developers of Btooom!, just exactly as Ryōta had deduced. Though he also unravels a handful of other information the two do not possess: the Btooom! project is being financially supported by an organization comprised of powerful corporations that unify themselves online (Themis), their escape plan has already been noted due to the IC chips monitoring their owners and is also expected to be easily dealt with by Tyrannos Japan via activating the safety locks on their BIM. 
Tsuneaki then instructs them that they must destroy the Btooom! project by escaping. And although Ryōta protests, requesting that Tsuneaki rescue both him and Himiko right away, Tsuneaki urges them further, soon succeeding in motivating the two to follow through with his request. He then teaches the two on how to bypass the safety lock by exploiting a glitch within both the timer BIM and blazing gas BIM through the removal of their casing. As soon as he finishes, he proceeds to walk back to the helicopter's location, stating he'll look for internal loopholes. Ryōta, however, attempts to follow but soon ceases as Tsuneaki points a gun at him, telling the boy to not follow him. Tsuneaki later returns to Iwamoto's side, telling him that the power plant is in good condition for them to finish the server maintenance. Afterward, the two board the helicopter back to the Tyrannos Japan company building. As the two discuss the repairs onboard the helicopter, Tsuneaki explains to Iwamoto that with the new implements written in the server, players with more than one IC chip will now have the advantage of a larger radius when using their radar, making it easier to locate one another. Eventually, the two arrive back to the company building, where a thankful Gemu awards them with time off from work. However, Tsuneaki declines this offer, making Gemu more suspicious of Tsuneaki's actions.
Much later, during the escape attempt made by Ryota's group, he is seen smiling, already knowing that he's played his own role in the escape and that Ryōta must now play his. After the helicopter and its crew were destroyed, Tsuneaki is seen deeming the success of their plan after believing that the flaws in the game have been shown. However, much to his dismay, he later finds out that the Btooom! project has been approved.