Coser was a Beta-grade technician who single-handedly developed IMIPAK at the Federation's Weapons Development base. Realising that his superiors were going to take all the credit for his invention, he destroyed all records of his work and fled with IMIPAK and the slave woman Rashel to an unnamed planet.
His movements had been predicted by the psychostrategist Carnell, however, and knowing his admiration for Blake, Servalan sent a Blake clone to him. He gave the clone IMIPAK, who in turn handed it over to Servalan. He was killed by her, using IMIPAK.