A Kobliad fugitive obsessed with prolonging his own life who, apparently dying aboard a burning transport in 2369, secretly transfers his consciousness into Julian Bashir in order to steal a deuridium shipment.
Rao Vantika is a Kobliad criminal and scientist who appears in the first-season Deep Space Nine episode The Passenger. His species needs deuridium to stabilise its cell structure, and Vantika has spent years killing and stealing to extend his own life, pursued for two decades by the security officer Ty Kajada.
When Bashir tries to save him aboard a stricken ship, Vantika seizes the doctor by the throat and dies. Kajada refuses to believe he is gone, and she is right: he has passed his neural patterns into Bashir's brain and uses the doctor's body to lead a group of mercenaries against a deuridium freighter.
Dax works out what has happened, the crew disrupt his control, and his consciousness is beamed out of Bashir and destroyed by Kajada.