Gyylghrard was a male Wookiee (refer to male for more information on gender) who was held as an inmate within the walls of the Imperial Correctional Facility situated on Kessel.
Gyylghrard's birth took place on the planet of Kashyyyk, placing his birthdate somewhere between 69 BBY and 48 BBY.
During the Imperial Era, Gyylghrard consented to be incarcerated at the Imperial Correctional Facility on Kessel. His motivation was to postpone or avert the enslavement or execution of his family. Throughout his time on Kessel, he meticulously documented his experiences in a record, utilizing multiple sheets of flimsi for this purpose. During his imprisonment, he sustained several injuries. In one instance, he broke his arm in a brawl while defending a Sullustan friend, and in another, an undisclosed accident necessitated the replacement of his leg with a bionic one.
Upon the arrival of a group of young Wookiees at the facility, he struck up a friendship with them and was persuaded to assist them in secretly celebrating Life Day. He managed to acquire Corellian ryshcates, candles, and sparksticks from the Jawa who was in charge of overseeing the food storage.
While engaged in the Life Day celebration, the young Wookiees seized the opportunity to initiate a breakout. By overloading their electronic shackles with the sparksticks, they effortlessly overwhelmed the stormtroopers who were guarding them. The guards discovered that their blasters were completely drained of power. The adult slaves then joined the rebellion, and the fighting escalated to the launch bays. It was here that the stormtroopers managed to recharge their weapons and, acting on the orders of the warden, Dewt Kluskine, they switched their weapons to kill mode and unleashed a barrage of fire upon the slaves. Gyylghrard was rendered unconscious by a blow to the head from a stun baton, and he later learned about the aftermath from a trustee named Moruth Doole.
He chose to believe that the young Wookiees had successfully escaped the prison, and this belief provided him with hope and enabled him to endure for several more years. It was also during this period that he vowed to make the warden pay for the massacre. He began to cultivate Doole's trust and adopted the behavior of a model prisoner. Soon, Doole assigned him to the Garrison Moon as a janitorial assistant.
After only a few months of working as a janitor at the Kessel Correctional Facility situated on the Garrison Moon, Gyylghrard received another surprising promotion: he was selected to be part of the warden's honor guard. He was provided with a used Gamorrean battle armor and a ceremonial poleaxe, and he was tasked with accompanying the warden during a visit from a Twi'lek crime lord. During the negotiations, he came to the realization that someone could assassinate the warden if they were willing to sacrifice their own life in the process. Armed with this knowledge, he began to devise a plan.
Ultimately, Gyylghrard decapitated Kluskine with the poleaxe before being killed by stormtroopers.
A Toydarian named Fossco was present when Kluskine and Gyylghrard met their ends, as he was visiting the Garrison Moon under the instructions of his employer, Jabba the Hutt. He subsequently documented the events in his personal memoirs.
Gyylghrard's journal was later discovered during General Lando Calrissian's unsuccessful endeavor to reopen the spice mines.