Her work to keep the lights on in Lestallum is what keeps the daemons out and keeps the town safe in turn.
Holly is a middle-aged woman with middle-parted shoulder-length hair. She is always seen wearing a version of the EXINERIS thermal suit.
Holly is dedicated to her job, and revealed that she can hardly say no to orders from the higher-ups, even at the cost of her health. She holds authority over other workers as a veteran technician and is always called to end disputes between the tough workers. She has a big fear of daemons, affecting her back.
Holly is involved with inspecting the valves and pylons around and outside Lestallum. When the EXINERIS plant was overrun by daemons, Holly went through so much shock she hurt her back. Noctis and Gladiolus eliminate the daemons, earning her admiration. She helps them to treat the mythril ore needed to power King Regis's boat. She calls Noctis her favorite hunter when he volunteers to inspect valves around Lestallum and pylons outside the city.
Holly also appears with Cindy in the Final Fantasy XV: Assassin's Festival, where she gives Noctis and his entourage their festival outfits. She is arrested by Loqi Tummelt for refusing to cooperate when the Niflheim Empire arrives in their search for Noctis. Hearing that Holly has been taken captive spurs Cindy and the party into motion to rescue her and drive the imperials out of Lestallum so the festival can continue.
Holly dedicates her life to keep the lights on Lestallum to repel daemons. When the world is encroached by darkness Lestallum becomes mankind's only safe haven, and Holly realized she could not defend the outpost alone. She began grooming her staff with an eye toward the future. Jeanne Labreigh is her apprentice.
Holly sends the party out to quests in behalf of the EXINERIS power plant.