Jason is a powerful Roman demigod and son of Jupiter, characterized by his signature short cropped blonde hair, electric blue eyes, and a distinctive scar on his lip. Raised by wolves at the Wolf House and trained at Camp Jupiter, he rose to the rank of praetor due to his disciplined nature and strong leadership skills. Often carrying the weight of high expectations and burdened by a deeply ingrained sense of duty, Jason served as a core hero of the Prophecy of Eight, balancing his rigid Roman upbringing with the more improvisational Greek traditions of Camp Half-Blood.

Piper is a Greek demigod, daughter of Aphrodite, and Head Counselor of Cabin 10. Despite her heritage, she rejects traditional vanity, preferring a tomboy aesthetic. She is a fierce, sword-wielding warrior armed with the blade Katropis and the rare, powerful ability to charmspeak people into following her commands.

Hazel is a Roman demigod daughter of Pluto with a striking and memorable appearance, characterized by her bright, gold-colored eyes and a thick mane of curly, cinnamon-brown hair. Originally born in the 1920s before being resurrected in the modern era, she possesses a gentle, sweet, and deeply empathetic nature, yet she carries a heavy emotional burden due to her past and a curse that causes precious gems and metals to rise from the earth around her.

Frank is a major demigod notable for being a son of Mars, the Roman god of war, and a descendant of Poseidon, which grants him a unique mythical lineage. Initially introduced as a clumsy, insecure, and bulky teenager of Chinese-Canadian descent, Frank undergoes massive physical and emotional growth throughout the series, evolving into a tall, muscular, and confident leader who eventually becomes a Praetor of the Twelfth Legion Fulminata. He possesses the rare, inherited ability to shapeshift into any animal he chooses, making him a versatile and formidable powerhouse in battle. Despite his incredible strength and deadly archery skills, Frank is defined by his gentle, fiercely loyal, and empathetic nature.

As the daughter of Bellona, she served as Praetor of Camp Jupiter, where she earned the unwavering respect of her legion through her exceptional leadership, tactical brilliance, and unparalleled combat skills. Beneath her tough, pragmatic exterior, she possesses a deeply compassionate heart and ultimately found strength and self-worth within herself.

Beneath his humorous, fast-talking, and heavily sarcastic exterior lies a deeply tragic backstory and an inherent feeling of being the unwanted "seventh wheel". Heart broken after losing his mother in a tragic fire manipulation accident as a child.