If I had to name one person I admire, it would be Simo Hayha. A sniper during World War II, he fought for 100 days. In that 100 days, he took down 542 people with a bolt action rifle and an extra 200 with an SMG. He had counter-snipers and artillery strikes sent at him, and they didn't touch him for 100 days, at which point he was finally hit in the jaw by an exploding bullet. Despite that, he woke up about a week later, and lived to the age of 97. He hadn't even been enlisted at the time he first started out.
Why do I admire him? He fought for what he believed in bitterly, holding his own and becoming a one-man army because of it. He didn't have to. He wasn't enlisted. But he did anyway, risking life and limb, and becoming a legend in the process. That, to me, is what it means to be a hero. Yes, he was a killer. But he risked everything for his beliefs.