Not much is known about Tobias's appearance, save that he is revealed to have curly brown hair and blue eyes, seeming to be no more than nineteen years old, as Thea Harman describes him as "college-age".
Initially, Tobias is shown to be bored and somewhat nonchalant about his job as Grandma Harman's apprentice, especially as it prevents him from seeing other witches he is fond of (being a rare male among witches, Tobias is known for his popularity among local female witches). However, the Crone's strength and stern manner is enough to keep him in line, and when she is present he obeys her without question. Due to his shortcomings and her own demand on him, Grandma Harman early on views her apprentice as "good-for-nothing".
By the time of Witchlight, the two appear to have come to a mutual understanding as Tobias matures and grows in strength from Grandma Harman's teachings; when meeting Keller's team, she insists that they "speak freely" before Tobias, whom she appears to trust completely.
As mentioned before, being male, Tobias is in high demand among other witches, and he is shown to have been seeing at least three girls at once, including one member of Circle Twilight.
Living in Las Vegas with the Crone, Tobias is present to bring Thea and Blaise Harman to their sixth high school, having been expelled from others around the country. After lecturing the girls, when Grandma Harman gives Tobias the command to return home, Thea notes that he has "the dazed and beaten expression all Grandma's apprentices got after a few days". He is additionally forced to sleep downstairs in the workshop of the Harmans' store.
While the oldest Harman goes to ask Thierry Descouedres if the Inner Circle can use his desert property for their Samhain celebration, Tobias is left to mind the shop, although this deeply bores him. Fortunately for him, Thea, seeking to conduct a forbidden rite to summon a spirit, allows Tobias to have the rest of the day off. Joyful, he warmly thanks Thea, promising to return to pick up Grandma Harman, and then departs, intending to visit one of his girlfriends.
When Grandma Harman falls ill from the accidentally release of the murderous witch, Suzanne Blanchet's, spirit, she is escorted home by two of Thierry's servants, complaining that Tobias never came to get her.
Tobias is present when Grandma Harman is sent to Vivienne Morrigan's mother to be healed; he reassures Thea that her grandmother wasn't "too bad", despite needing a healer. Worried for Thea, the witch Dani Abforth allows Tobias to go out on another date after Blaise and Vivienne leave to spend the night at the Morrigans' home.
It is revealed, near the end of the book, that Tobias had been spying on Blaise and Thea, and one of Tobias's dates, Sheena, a member of Circle Midnight, had been the one who reported Thea's actions to the Inner Circle.
Tobias accompanies Grandma Harman to the Circle Daybreak safehouse, where the shapeshifter operative Keller and her team have secured Iliana Dominick, a lost Harman and the Crone's grand-niece. She allows the group to speak before him, explaining his role. He additionally plays the secret video tape of the two known Wild Powers using their abilities to show Iliana what she is capable of doing.
When operatives from the Night World, acting along with the dragon Azhdeha, Tobias and the witch Winnie Arlin use witchlight to fend off the attacks, the Crone's apprenctice right between her and the enemy, even fighting a Night World ninja. He is present when Azhdeha crushes the safe house with Power, although both he and Grandma Harman emerge unharmed, helping unearth the severely injured panther when Keller shifts to try to protect them all. Before departing, he, Winnie and Grandma Harman successfully heal Keller of her wounds.
It is unknown if Tobias was also killed along with the Crone when she had been murdered outside her shop by renegade shapeshifters. He has thus far not appeared in the series again after this incident.
- Like other witches later in the series, it is shown that Tobias can use witchlight.
- Tobias's last name is never revealed, therefore it is not known what clan of witches he hails from.
- Technically, Tobias's given name may not be deemed a traditional witch name, as it comes from the Hebrew and means "God's Goodness". However, it possibly fits as, being polytheistic, the witch clans worship many different gods and goddesses, and might include the Judeo-Christian God among their deities.