Pac, also known as Pac-Man and Pacster, is the main protagonist of the animated series Pac-Man and the Ghostly Adventures. He is a teenage Pac-Worlder and the last of the Yellow Ones, a nearly extinct group of yellow Pac-People. After his parents, Zac and Sunny, disappeared during the war against Commander Betrayus, Pac was orphaned and raised by his Aunt Spheria. He attends Maze High School in the city of Pacopolis, where he lives in the school dorms with his friends. His real name is Pacster, but he came to be called Pac-Man after he took on the role of hero. The central conflict of his life begins when he accidentally breaks the seal to the Netherworld while fleeing from the school bully Skeebo, releasing Betrayus and his ghost army into Pac-World.

In personality, Pac is brave, cheerful, kind, loyal, and compassionate, with a genuine desire to help others and make the world a better place. He is also humble and does not flaunt his status as a famous hero. At the same time, he is impulsive, rebellious, immature, and at times absent-minded. His most defining trait is his enormous appetite; he is almost always hungry and can be strongly motivated by food, sometimes to the point of neglecting more serious matters. Despite his occasional recklessness, he is good-hearted and genuinely wants to protect those around him.

Pac's main motivations are to defend Pac-World from the ghosts, to prove himself as a hero, and especially to find his long-lost parents, whose fate remains a driving personal goal throughout the series. His role in the story is that of the primary hero: he regularly battles Betrayus and his forces, rescues Pac-Worlders, and works to undo the chaos caused by the ghosts he inadvertently released.

His key relationships include his two best friends and fellow students, Cylindria, an intelligent and sassy pink Pac-Girl, and Spiralton, a tall, athletic red Pac-Worlder. The three of them work together as a team, with Pac often leading the adventures. He is also close to his Aunt Spheria, who raised him. Unusually, he forms an alliance with the Ghost Gang, a group of four friendly ghosts named Blinky, Pinky, Inky, and Clyde, who secretly help him in exchange for his promise to restore them to the living world. Pinky in particular has a crush on Pac, though he remains largely unaware of her feelings. His main enemy is Lord Betrayus, the ruler of the Netherworld, while Skeebo serves as a rival and bully at school.

Over the course of the series, Pac develops from an ordinary, carefree teenager into a more responsible and capable hero. He gradually grows more accustomed to his heroic duties, and some episodes show him confronting his own flaws, such as his lack of self-control around food. However, he remains the same cheerful, food-loving character at his core.

Pac's notable abilities come from his heritage as a yellow Pac-Worlder, which grants him the natural power to eat ghosts and spit out their eyes. His fighting potential is greatly increased by Power Berries from the Tree of Life. When he eats one, he transforms for battle and gains a variety of powers depending on the berry; for example, the yellow berry allows him to fly, survive in the Netherworld, and more effectively consume ghosts. Other berries grant additional temporary abilities, such as enhanced intelligence or other specialized powers. These transformations make him the most effective defender of Pac-World against the ghost threat.