Jim Lake Jr is a 15–16-year-old human teenager at the start of the series (later 16–17, and 17–18 in Rise of the Titans). He is of average height for his age, slim, with short dark brown hair and blue eyes.
He is the main protagonist: an ordinary middle-schooler who finds the Amulet of Daylight and becomes the first human Trollhunter, tasked with protecting both humans and trolls.

His personality blends bravery, responsibility, and strong loyalty with typical teenage doubts; he often worries about failing his friends and family, can be impulsive when protecting them, and gradually matures into a more confident leader while staying empathetic

Claire Nuñez is about the same age as Jim (15–16 in Trollhunters, 17–18 later). She is of average height, slim, with dark hair (notably with a blue streak that later turns white after her connection to the Shadow Staff), brown eyes, and a warm complexion with freckles.

Her role evolves from Jim’s classmate and love interest to a core member of the Trollhunters and later a powerful magic user wielding the Shadow Staff (Skathe-Hrün).

Personality-wise, she is intelligent, sharp-tongued, and independent; she can seem irritable or guarded at first, but is deeply caring, protective of her brother and friends, and grows into someone emotionally resilient and morally strong

Toby Domzalski is also 15–16 at the beginning (later 17–18). He is shorter and stockier than Jim, with brown hair, green eyes, and a rounder build
He is Jim’s best friend and the deuteragonist: though not the chosen Trollhunter, he becomes an essential fighter and companion, wielding a warhammer and joining Jim on almost every mission.

His personality is optimistic, loyal, and humorous; he provides comic relief but also shows real courage and creativity in battle, acting as the emotional heart of the group and standing by Jim even in the toughest moments

Blinky is an elderly troll with a distinctive look: blue-green skin, six eyes (four smaller ones around two main ones), curved horns, four arms, and a scholarly, slightly hunched posture. His exact age isn’t given in human years, but he is portrayed as a very old, experienced troll.

His role is mentor and strategist: a former royal tutor among trolls, he becomes Jim’s primary guide, teaching him troll culture, tactics, and the ethics of being the Trollhunter. Personality-wise, Blinky is wise, patient, and somewhat theatrical in speech; he can be strict or pessimistic, but his deep loyalty to Jim and his hope for a better future for trolls and humans make him a fatherly, morally grounded figure.

very tall, with gray-blue skin, large horns, and an imposing, brute-like once a general of the Gumm-Gumm army, he renounces violence, becomes Blinky’s close friend, and later forms a strong bond with Toby. serious due to his traumatic past, but guided by a strong code of honor and deep loyalty to his friends, especially Blinky and Toby.