Ryler Dorant, also known as Needles, was a male human who was a lieutenant in the Havoc Squad, an elite team of Republic troopers serving in the military of the Galactic Republic. Dorant was a medical genius and was particularly adept at synthesizing powerful new combat stimulants and adrenals.
He, along with most of Havoc Squad, defected to the Sith Empire shortly before the end of the Cold War.
Needles eventually traveled to Taris and weaponized the rakghoul plague. With the intention of making it fast acting, he planned to test it on newly defected Republic troops, Imperial troops and captives brought to him by the Death's Claw pirates of Fallenspire Stronghold.
Soon after he finally succeeded in creating a nekghoul with his newly created weapon, the Havoc Squad, led by the original member who did not defect, managed to stop and kill Needles, ending his experiments.