Heavy is a clunky, silver robot created by Dr. Ivo Robotnik in 3235. Designed to tap into any database and act as a system's repair unit, both he and Bomb were one of the few robots created by the despot that had their own free will, which was what resulted in Heavy and Bomb abandoning Dr. Robotnik and joining the Chaotix. They would subsequently join the Royal Secret Service before being reprogrammed by Dr. Eggman, only to be destroyed. Eggman subsequently rebuilt them, only for them to suffer destruction; the Freedom Fighters later rebuilt these new models with the personalities of their former selves to serve on Team Freedom.
Creation and Defection
Heavy was created in 3235 along with his counterpart Bomb, both created to act as "mechanical mechanics, designed to seek out and repair damaged systems automatically". However, because Robotnik used Power Gems to power them, Heavy and Bomb developed consciousness and consciences. When the two discovered Robotnik's schemes to trap the Knothole Freedom Fighters in the Hall of Mirrors at Happyland Amusement Park, they left Robotnik and joined the Chaotix to help them stop Robotnik's plans. When Metal Sonic attacked the Chaotix, Heavy and Bomb aided in their efforts to destroy him. (KCX)
In the Secret Service
Some time after this, Heavy and Bomb sought out a place to fit in. Due to Heavy's ability to tap into Robotnik's database, he researched information regarding Geoffrey St. John and finally went to him in Knothole to join the Royal Secret Service. Realizing their potential, Geoffrey recruited them. (StH: #62)
Heavy and Bomb's first mission took them to Angel Island once again, this time to discover what had become of Queen Alicia during the Great War. The Secret Service successfully discovered Queen Alicia alive though in cryo-sleep and brought her back to Knothole. (KtE: #19, #20, #21)
Following Sonic and Tails' encounter with Metal Sonic v2.5, the Royal Secret Service was sent to investigate the now-dormant site where they found Metal Sonic's slagged remains. Heavy determined Metal Sonic's core programming to be part of the still functional Power Gem. (SU: #43)
Some time later, Heavy and Bomb accompanied the rest of the Secret Service to Robotropolis to locate and retrieve the missing Sword of Acorns from Dr. Eggman. During this mission, the entire team was captured by Shadowbots. During their time in captivity, Eggman had each prisoner brought out one at a time to seem like they were being interrogated. In reality, this was a ruse to get Heavy and Bomb out of site so he could have them reprogrammed as sleeper agents. Following this, Heavy and Bomb blew up the jail's wall, enabling the Secret Service team to escape from captivity and return to Knothole. (StH: #97)
Controlled by Eggman
Following the rescue of the Robians from Robotropolis, Dr. Eggman activated Heavy and Bomb to begin attacking. Due to Nanites injected into the systems of Wombat Stu, Hershey Cat and Geoffrey St. John while in Robotropolis' jail, Bomb was able to incapacitate them by releasing a certain gas that activated the Nanites. Following this, Heavy sent the Bombs around all of Knothole, holding the Royal Family hostage. When Heavy explained he was the one who created all the Bombs, Sonic quickly smashed through and destroyed him before he could complete his sentence. Before the Bombs could detonate, Rotor and Tails disabled them with an EMP generator. (StH: #102)
In 3237, months after Sonic's return to Mobius from outer space, Dr. Eggman produced new models of Heavy and Bomb to assassinate the singing star Mina Mongoose after Nack the Weasel failed to do so. Heavy and Bomb went into the concert where the former attacked Sonic but when Sonic drilled beneath him, he fell in into an underground river. While Sonic fainted, Heavy continued to sink and was presumed destroyed. (StH: #153, #154)
Months later, Tails and Rotor rebuilt Heavy as well as Bomb, combining the cores with their original programs, and the body designs that Eggman from eariler. Both were repurposed to be members of Team Freedom to protect the city from incoming threats. "King" Naugus did not like the idea of two traitor Badniks working for them, but Rotor reminded him that he was bad once as well and they first rebelled against Dr. Robotnik. During the exchange, a side of the civic center gave way due to unknown causes, and Heavy worked alongside with Big to hold up the unsupported section as Team Freedom managed to prevent a disaster, earning the public's overall support. He and Bomb later joined in defending New Mobotropolis from Egg Swats and Team Metal, though Heavy expressed some initial reluctance given his history of being destroyed. Despite this, he performed heroically, and was even prepared to fight Metal Sonic v3.0, only to be unexpectedly relieved of that duty by Shard, an irony given that Heavy had originally battled that version of Metal Sonic. Heavy and his teammates later attended a concert thrown by Mina Mongoose and the Forget Me Knots, and saved the band when the stage collapsed underneath them. (StH: #236, StH: #240, #241)
After the source of the mysterious building collapses was revealed to be Tails Doll, Heavy and Bomb joined the rest of Team Freedom and NICOLE in lying in wait for the robot infiltrator at the city power plant. Unfortunately, Tails Doll responded by taking on a monstrous new form, intent on destroying the city and its defenders. (StH: #247)
After becoming sentient, Heavy has displayed a strong sense of justice and a desire to do good. He is something of an intellectual despite his powerhouse design, particularly displaying an expertise on Power Gems Both his reprogrammed original version and the Eggman incarnation prior to its reprogramming were blindly obedient to Eggman, desiring nothing more than the destruction of his enemies. Having been "reborn", Heavy displays a certain melancholy, fearing that he might not survive being destroyed a third time. Regardless, he is a dutiful soldier and faithful friend, though he is occasionally forced to reprimand Bomb.
- Heavy and his partner originated from the video game Knuckles Chaotix.
- The original versions of Heavy and Bomb featured their own unique designs. However, the rebuilt models were based directly off of their Knuckles Chaotix videogame appearance.
- It was said that Heavy could produce new Bombs but the process is not shown.
- Heavy and Bomb were known as the "Mechanix" in the Chaotix American game manual.