Billa

DSP Jayaprakash is a determined police officer who has spent years chasing the elusive underworld kingpin Billa. He secretly buries Billa after a fatal chase and orchestrates an undercover infiltration using a look-alike to bring down the gang. He trains Saravana Velu and uses his promise to educate Velu's adopted son, Karan, as leverage in the operation. His calculated ruthlessness creates moral ambiguity as lines between officer and operative blur.

David Billa is the feared underworld don who dies in an accident; Saravana Velu is a hotel server and small-time gangster who is recruited to impersonate Billa. Velu infiltrates Billa's gang, learns the network, and communicates with Jagdish. He provides a pen drive with the network's secret data to Jayaprakash. As events unfold, Velu navigates danger to protect Sasha and Karan and ultimately helps expose Jagdish.

Jagdish is Billa's boss and the mastermind behind the crime network. He is revealed to be Gokulnath, an Interpol officer who manipulates events to capture Velu. He coordinates with the police to frame Velu and tries to seize control by threatening Sasha and Rhea. In the climactic gunfight, he is shot by the police after their wiretapped conversation proves Velu's innocence.

Sasha is Billa's girlfriend who carries the memory of her brother Rajesh's death and seeks vengeance. She confronts Velu, believing him to be Billa, and remains fiercely protective of Karan. Her allyship is tested as she becomes a target of Jagdish's schemes and is kidnapped during the conflict.

CJ is Billa's girlfriend and a member of his inner circle. She overhears Velu's plans and confronts him during a tense moment. She is killed in the struggle when Velu is forced to defend himself during a confrontation at the party.

Anil Menon is a police officer who plays a pivotal role in the pursuit. He appears to hold the pen drive and uses Velu to corner Jagdish. He negotiates a deal to ensure Jagdish's capture, thereby influencing the outcome of the case.

Rhea is Rajesh’s fiancée and Sasha’s ally, caught in the web of Jagdish's schemes. She is kidnapped by Jagdish along with Sasha, becoming a leverage point in the pursuit of the pen drive. Her fate underscores the personal costs of the gang warfare.

Karan is Velu's adopted son, a key emotional anchor for Velu's mission. He becomes the reason Velu agrees to infiltrate Billa's gang, and Jayaprakash promises to ensure his education. Karan represents hope and the human stakes behind the counter-crime drama.

Rajesh is Sasha's brother who, along with his fiancée Rhea, was killed by Billa earlier, fueling Sasha's vendetta. His memory and loss drive Sasha's actions and add personal stakes to the conflict.

Ranjith is an ally who assists Velu with information and support. He becomes a risk when he tries to kill Velu during a confrontation, and is ultimately neutralized as Velu fights to prove his innocence.