Optimus Prime Role: Autobot Leader Alt Mode: Peterbilt-style semi-truck Height: About 30 feet (9 meters) Personality: Calm and patient Inspirational leader Compassionate toward both Autobots and humans Always puts others before himself Skills: Expert swordsman Master tactician Exceptional hand-to-hand fighter Weapons: Ion Blaster Energon Swords Star Saber Forge of Solus (later in the series) Relationships: Deep friendship with Ratchet. Mentor to Bumblebee and Smokescreen. Long history with Megatron, once known as Orion Pax.

Ratchet Role: Chief Medical Officer Alt Mode: Search-and-rescue ambulance Personality: Sarcastic Brilliant scientist Protective of his teammates Acts grumpy but deeply cares for everyone Skills: Engineering Medical treatment Computer programming SpaceBridge technology Interesting Facts: Often repairs Autobots after battles. Can hold his own in combat despite being a medic. One of Optimus Prime's oldest friends.

Bumblebee Role: Scout Alt Mode: Yellow sports car Personality: Friendly Brave Optimistic Protective of Raf Skills: Espionage Speed Excellent marksman Weapons: Arm blasters Stingers Interesting Facts: Lost his voice before the series. Speaks using electronic beeps. Regains his voice during the series finale.

Arcee Role: Scout/Special Operations Alt Mode: Blue motorcycle Personality: Independent Loyal Fierce Protective Skills: Martial arts Stealth Acrobatics Dual-wield combat Weapons: Twin blasters Wrist blades Interesting Facts: Lost her partners Tailgate and Cliffjumper. Develops a close friendship with Jack Darby. Often serves as the team's fastest responder.

Bulkhead Role: Heavy Weapons Specialist Alt Mode: Military SUV Personality: Gentle Funny Loyal Loves art Skills: Incredible strength Heavy lifting Demolitions Weapons: Wrecking-ball fists Massive physical strength Interesting Facts: Former member of the Wreckers. Best friends with Miko. Surprisingly talented artist.