A veteran Autobot warrior, Overhaul fought alongside Optimus Prime in the Unicron Battles and Powerlinx Battles, with service extending beyond those conflicts. He exhibits a gruff, confrontational demeanor and professes a preference for working alone. However, he holds deep loyalty to the Autobot cause and an understanding of friendship and teamwork's value. This complexity arose from a pivotal Decepticon skirmish where, charging in without backup, he became trapped under a massive boulder. Rescued and defended personally by Optimus Prime, Overhaul learned a lesson in camaraderie. Yet, his independent streak persisted, fueled partly by bitterness after overhearing fellow Autobots criticize his recklessness, reinforcing his belief in self-reliance. When the Unicron Singularity threatened Cybertron, Overhaul joined Optimus Prime's unit on Earth to find the Cyber Planet Keys to restore the Allspark. He applied stealth coating during base construction to evade Decepticon detection. On missions, he often partnered with Landmine, scouting ancient sites for the Omega Lock and responding to distress signals, frequently encountering Decepticon interference. His impulsive nature emerged during the search for the Jungle Planet's Cyber Planet Key; against advice, he directly confronted the planet's ruler, Scourge, demanding the key. This resulted in a brutal defeat where Scourge nearly destroyed him before Snarl intervened. Seeking strength, Overhaul underwent rigorous training by submerging in lava at a volcano to withstand Scourge's fire attacks. In a subsequent rematch, he defeated Scourge's subordinates, Undermine and Brimstone, but Megatron intervened, throwing Snarl into Overhaul. When Scourge attacked the helpless Snarl, Overhaul shielded him. This act triggered an emergency transformation using the Jungle Planet's Cyber Planet Key energy, rebuilding him into Leobreaker. As Leobreaker, his gung-ho attitude intensified while his independence diminished significantly. He forged a fast friendship with Snarl, gained Mini-Con attendants, and developed an interest in Earth team sports like baseball, potentially as a peacetime substitute for war. This shift emphasized teamwork, though he privately resented that his combination with Optimus Prime—Savage Claw Mode, where he forms a powerful claw-arm—might not be as effective as Optimus's Sonic Wing Mode with Wing Saber. Leobreaker frequently utilized Savage Claw Mode against Megatron and Scourge. However, during a confrontation where Optimus attempted peaceful resolution with Scourge, Leobreaker impulsively separated to fight alone, resulting in defeat. Scourge spared him, acknowledging honorable combat. Retreating to the volcano to sulk, Leobreaker received counsel from Snarl, prompting reflection on his past as Overhaul and reconciliation with Optimus, recognizing the leader's consistent support. This evolution marked his journey from a solitary warrior to a team-oriented fighter. Originally conceived as "Trailbreaker" to align with his "Leobreaker" upgrade, trademark issues led to the name "Overhaul," while the lion-based upgrade name remained. His color scheme pays homage to Generation 1 Brawn, a secondary choice after an abandoned Outback-inspired palette. In robot mode, he features a feral design with Wolverine-like claws and angled forearms, while his vehicle mode is a green 4x4. After transformation, Leobreaker adopts a robotic lion alternate mode, emphasizing his connection to the Jungle Planet's ethos of strength.