I don't know if I'm gonna get any hate because of this since he's such a controversial character but I must say that Griffith from Berserk is one of my favourite characters of all times and that's mainly because of how human he is.
While he's an excellent swordsman and tactician he's also very...
Ergo Proxy (classic), Mononoke, Perfect Blue (movie), Mahou shoujo Madoka Magica (don't be fooled by its name or appearance), Mousou Dairinin (really good), Kino no Tabi; the beautiful world (can only speak for the original series as that's the only one I've seen), Gunslinger Girl and Jin-rou...
yikes well if I were to judge it based on how many attempts it took for me to beat the boss then:
1. Midir from DS3 - mind you no cheese strats or summons.
I actually didn't find him that hard, just annoying because of the hitboxes. Non humanoid bosses have always been easier for me to handle...