Gantrell was a scientist of the Human species and male gender. He was stationed on Belsavis during the time of the Galactic War, a conflict between the Galactic Republic and the re-emerging Sith Empire.
Around the year 3641 BBY, Gantrell was employed by the High Security Section. His research focused on the Rakatan hyperspace power core. However, he was eventually apprehended by Executor Krannus. Subsequent to his capture, Gantrell managed to transmit an emergency signal to Pak Taldine. He was subsequently imprisoned in Vault S-31 and abandoned to his death. When the Hero of Tython showed up and eliminated an ancient Sithspawn known as a terentatek, Gantrell, in a state of fear, revealed Krannus's plan to trigger the planet's core. This detonation would unleash a hyperspace shockwave, engulfing not only Belsavis, but also its entire system and all neighboring star systems. Gantrell pleaded with the Hero to not abandon him within the perilous vault. Consequently, the Jedi consented to secure the doctor inside one of the vault's shielded compartments before venturing further into the prison complex.