Guts has what could be the most complex personality in the entire series. It could be said that due to this complex personality, he is perhaps the most "human" out of the characters introduced, demonstrating significant shifts in character as he ages.

Being born from a bloody situation and forced into a life of violence, Guts had hardly any time to live like a normal child. While he experienced moments of happiness and joy, his true passion was warped into desiring the fight, mostly to gain Gambino's favor and later to satisfy his own fighting abilities. After successfully killing the first person he would in a list of thousands, Guts tempered himself to become stronger and know how to hold his sword, eventually building a strong and very personal relationship with the blade he wields. During his time with the Band of the Hawk, Guts had also told Casca that he was only ever happy when wielding his sword.