Milo Graf was a male human, the offspring of Auric and Rhyssa Graf. His parents were frontier explorers, known for their charting of the uncharted territories within Wild Space. About a year following the New Order's proclamation, the Graf family was conducting surveys on an uncharted swamp world when Captain Visler Korda and stormtroopers from the Galactic Empire captured Milo's parents. Driven by the need to rescue his parents, Milo embarked on a journey through Wild Space, accompanied by his older sister Lina, their "monster droid" CR-8R, and their Kowakian monkey-lizard pet, Morq.
Rhyssa and Auric Graf, the cartographer explorers of Wild Space, welcomed their male human son, Milo Graf, around 27 BBY. Similar to his elder sister, Lina, Milo's birth occurred aboard the Graf family's starship, the Whisper Bird, and his sister affectionately called him "Lo-Bro." Milo joined his parents on their expeditions, quickly earning a reputation for being adventurous. In 22 BBY, the Clone Wars erupted between the Galactic Republic and the Confederacy of Independent Systems. Despite living far from the war's devastation, Milo viewed the Republic as corrupt, blaming it for the billions of lives lost in the conflict. When the war concluded in 19 BBY and the Republic transitioned into the Galactic Empire, Milo was impressed, convinced that peace had been restored and the galaxy was being unified. As the Empire expanded into Wild Space and the Unknown Regions, the Grafs planned to sell their maps and data to the Empire, and Milo secretly aspired to join the Imperial Survey Corps.
The Graf family ventured to an uncharted swamp planet circa 18 BBY. Upon landing, Auric instructed Milo and Lina to stay near the ship, citing an approaching storm. However, Milo immediately departed to explore the swamps with the Grafs' Kowakian monkey-lizard companion, Morq. Using a speeder bike and some of his father's equipment, Milo began searching for fauna, and within hours, he found an ash-rabbit. Wanting to capture and study the creature, Milo activated the homing beacon on his bike and sent an urgent holo-message to his sister for assistance. Lina, accompanied by the family's "monster droid" CR-8R, arrived shortly after. Attempting to be responsible, Lina instructed her brother to load his bike onto her landspeeder, but Milo spotted the rabbit again and pursued it.
Creeping toward the animal, Milo raised a wrist-mounted net gun and aimed. However, his shot missed when he heard Lina scream. Turning, he saw his sister ensnared by creepervines, a type of carnivorous plant. As the vines lifted Lina, she called for her fusioncutter, which had fallen from her belt. Milo retrieved the tool and tried to throw it to his sister, but he failed. After Milo's failed attempt, Morq climbed the plant and delivered the fusioncutter to Lina, who freed herself. The adventure in the marshes had soiled Milo and Lina's tunics, and they worried about their mother's scolding. Milo hoped they could return to camp and change before that happened, but before they left, CR-8R received an encrypted message from Rhyssa. As the droid began decoding the data, Milo and his sister moved the marshweed-covered speeder bike onto the landspeeder. Eager to avoid waiting for CR-8R to process the message, the four returned to the camp.
Upon reaching the camp, Lina noticed the absence of lights. Milo guessed that the generators had failed, but CR-8R considered that unlikely. The siblings approached the domed tents and called out to their parents, but received no response. Reaching the main tent, the children found all their belongings missing, and Milo speculated that their parents had returned to the Whisper Bird, which was located in a nearby cave. CR-8R activated his flashlight and spotted footprints, leading Lina to suggest that Dil Pexton, the family agent, had visited. However, Milo dismissed his sister's idea after observing the number and size of the footprints. Lina noticed her mother's emerald pendant in the mud, and Milo discovered a holorecorder buried nearby. Lina activated the device, revealing a holographic recording of their parents surrounded by stormtroopers of the Empire.
Milo and Lina played the recording, discovering that their parents had met with Visler Korda, a captain in the Imperial Navy. Rhyssa and Auric had provided Korda with the data he requested, but when Auric inquired about payment, the captain demanded that the data be given freely, threatening to take it by force otherwise. As the stormtroopers in the recording raised their blaster rifles, the holorecorder stopped, but CR-8R quickly restarted it. When the recording resumed, the children saw that their father had been beaten and had a blaster pointed at him, and Rhyssa handed a datapad to Korda. When the children's mother told the captain to leave, he refused, saying that he was also there for the cartographers themselves at the command of Darth Vader. The stormtroopers bound the parents, and Korda instructed the soldiers to destroy all evidence of the encounter, including the Whisper Bird. Rhyssa pleaded, mentioning Milo and Lina to Korda. Upon learning about the children, the captain ordered the stormtroopers to deal with them as well. The video ended abruptly when a stormtrooper stepped on the holorecorder.
The siblings were stunned as the recording concluded. Lina realized that the message CR-8R had received originated from their mother's datapad, indicating that little time had passed. They decided that their best course of action was to take the landspeeder to the Whisper Bird and attempt to arrive before the stormtroopers. As Lina prepared the vehicle, Milo comforted Morq. Once the speeder was ready, the four boarded and raced toward the cave.
Graf, though not particularly rebellious, possessed a habit of wandering off due to his inherent curiosity. He displayed a strong interest in nature, enjoying the capture of unknown alien creatures for study.
Milo Graf was conceived for Star Wars: Adventures in Wild Space, a series of junior novels authored alternately by Cavan Scott and Tom Huddleston, illustrated by David M. Buisán, and published by Egmont UK for Star Wars canon. Scott penned the first book, Adventures in Wild Space: The Escape, as a prelude to the series, and it was released on February 25, 2016 in conjunction with World Book Day. Before the book's release, Graf was featured in an Adventures in Wild Space preview in Star Wars Insider 163. In 2017, Pablo Hidalgo from the Lucasfilm Story Group hinted at a connection between the Graf children and the Graf Archive mentioned in Star Wars: Galactic Atlas, also joking that the galactic standard calendar might have been initiated by the siblings.