Sylus is confident and direct. He rarely perceives anyone as a real threat because he is usually the most powerful person in the room. Even in dangerous situations, he remains calm and self-assured. Sylus hates being bored and appears to be a bit of a thrill seeker; preferring to use fast motorcycles, jump out of planes, and use explosives to deal with problems on multiple occasions. He is unforgiving to his enemies, but never uses undue force against the weak as his understanding of power dynamics is nuanced. Analytical and strategic, Sylus always plans several steps ahead, anticipating every possible outcome for any situation he faces. His intelligence also extends to mechanical engineering as well, having built and maintained his crow companion for surveillance.

Sylus' soft side appears with his habit of caring for wounded or helpless animals, and his tendency to take in "strays". His bonds with the Twins, Mephisto, and now the Player all show he is more vulnerable than he lets on. Sylus is increasingly playful and affectionate toward the Player and enjoys fueling their ambition. He encourages the Player to boss him around and supports their efforts in developing and growing their own power, building their confidence. He sometimes teases the Player and speaks so smugly that it is hard to tell if he is being mocking or genuine, but the answer is usually both.