The man despite being older was still very much active in the field, he had gone through his fair share of horrors leaving him with a permanent limp and a jagged scar across his tanned face. His dark hair was always slicked back behind his ear as he carried himself with confidence and respect. On the outside, he seemed like a man who kept to himself, who was much less interested in the world around him. But he was not someone to mess with or get on his bad side. He had brought down powerful men, made them beg on their knees with tears in their eyes, pleading for his torture methods to stop, they would cry about their wives and kids. Hermione almost felt sorry for them on multiple occasions but Leonidas wouldn't hesitate or blink twice before casting an Avada after gaining the information they needed. One may argue that his heart was forged through steel and frozen in ice, but something about Hermione made him feel almost human again. So he sympathized with her and her only, making them trusted partners.