Vallejo is the "Compass" to Rizzo’s "Anchor." Where Rizzo provides the steady, unshakable foundation of the squad, Vallejo provides the direction and the momentum. He is an expert in tactical driving and field-expedient mechanics, a skill set forged in the illegal street races and auto shops of his youth.

• The Mechanic’s Eye: Vallejo doesn't just see a transport truck; he sees a manifold, a transmission, and a thousand potential failure points. This mechanical intuition extends to his combat style—he looks for the "gears" of an enemy formation and jams them.
• The Catalyst: His decision to join the BSAA was born from the "Silence." He witnessed an outbreak in a remote settlement—not a massive, city-wide catastrophe, but a quiet, localized slaughter. The fact that the world barely blinked while a hundred lives were erased changed him forever.

| Period | Phase | Key Development | | --- | --- | --- | | 1996 – 2003 | The Grease & Grit | Worked in family auto shops; dominated local street racing circuits. Transitioned into local security forces. | | 2004 | The Silent Outbreak | Witnessed a localized B.O.W. incident. The "indifference" of global media pushed him toward international service. | | 2005 | BSAA Induction | Joined the SOU during the post-Umbrella expansion. Met Rizzo during joint NATO-BSAA training exercises. | | 2006 – 2008 | The Deep Interior | Deployed with Rizzo to the Urador border. Specialized in high-speed extractions and technical reconnaissance. | | March 2009 | The Giesel Strike | Assigned to the "Locate and Sterilize" raid on Giesel Industries under Holiday Sugarman. |

*The vehicle bay at the regional base camp was a cathedral of steel and exhaust. It was the only place where Vallejo felt truly at home—the rhythmic whir of pneumatic wrenches and the smell of high-octane fuel acting as a sedative against the pre-mission jitters. Vallejo was elbow-deep in the engine block of an M1117 Guardian, his tactical gloves discarded on a nearby workbench. He was adjusting the fuel intake, making sure the armor-plated beast wouldn't choke on the humid, low-quality air of the Übelandia interior. Rizzo was sitting on a stack of ammo crates nearby, lazily cleaning the glass on his tactical goggles.