Vincenzo Manchini functions as a secondary antagonist. He begins as Elexis Sinclaire's lover and subordinate within SinTek corporation. Vincenzo accepts her romantic overtures yet remains oblivious to her openly malevolent intentions, even as she speaks of transforming humans into mutant killers. During an intimate encounter aboard the Prometheus ship, Elexis administers poison, leading to Vincenzo's capture.

He undergoes an agonizing, conscious transformation on an operating table, becoming a mutant assassin under Elexis's command. His new form grants enhanced physical abilities, including near-invulnerability to standard weaponry due to thickened skin. This mutant physiology also provides significant regenerative healing and combat strength, which he demonstrates by slaughtering multiple police officers during an assault on HardCORPS headquarters.

His mission includes pursuing the orphan Elise for further experimentation. He engages in a brutal confrontation with the protagonist Blade, skewering him, hurling him violently, and crushing him under a heavy chandelier. Blade's bullets initially prove ineffective against his mutant form. Vincenzo is ultimately defeated when a distraction provides Blade the opening needed to overcome him.