Theo has a negative aura about him. He feels abandoned by the gods. However, he also has an aura of leadership.
Theo was born in the old days, and I mean back when Ouranos was still around. When the war between the titans and the gods broke out, he sided with the titans, which was evidently the wrong side. Since he was fighting full gods, he was way out of his league, and as such quickly got his ass kicked. Zeus ordered his execution, but Hecate kept him, thinking maybe she could use him in the future. She put him into a state of magical stasis, where he stayed nourished, but didn't age. (She wanted him in prime condition). Years upon years later, she stumbled upon where she had left him, and decided to use him. It started out with trivial tasks such as fetching things for her, but eventually he proved himself and so she began using him for bigger tasks such as taking out enemies, or sending important messages. One day, he was tasked to take out a kid in the BC. He set out, ready to kill him, but the kid convinved him otherwise. Showed him how the gods were using him, and made him angry. So, with the help of the BC, Theo cut his connections with Hecate, and joined the ranks of Liberi Superum, determined to bring down the gods.