Hieronymus is of average height but rather thin. His hair is an unusual color, whitish (like the color of sea foam) with black tips. But what one remembers most about him are his eyes, dark blue with flecks of gold.

In formal setting he wears his Tremere robes of blue-black color, but while travelling or working in the lab he often switches to less elaborate robes of common colors. He often carries a walking staff.

Hieronymus does not speak much, for he feels less at ease with words than with actions. He will often use a gesture instead of a sentence, if he feels it can achieve the same result.

He truly believes in the ideals of House Tremere and sees his House as a protector of the Order, against the forces of chaos. With House Tremere, he found the family he didn't have as a young child. He will defend it and what it stands for.