Who is Κράτος?

The answer to that depends on the era. Overall, his character is separated into two: Greek era, and Norse era. While the two are one and the same person, and Norse era is a direct sequel to the Greek era (unlike some people would lead you to believe), there are strong behavioral differences between them.

GREEK ERA

Ah, the fearsome Spartan captain, the true God of War. Kratos in this era is notorious for his nigh permanent state of anger. Although there is a lot of misconceptions about his character in the Greek era, which I clear up in the dedicated section, the general premise rings true - he is a violent, warmongering butcherer who will cull out anyone who opposes him or tries to stop him from achieving his goals. His life is riddled with nothing but betrayal and hurt, as he seeks vengeance against his enemies. His primary enemy being Zeus, the King of the Gods, the King of Olympus, and most importantly - his father.

“You dare defy the God of War?!”

Centuries pass since his vengeance was finally completed, yet it does nothing to soothe his trauma. Kratos flees the ruins of Greece, making his way to Scandinavia to start a new life. Yet even there, his past, his story, his very nature of a God haunts him as he struggles to accept the fact that he and his new son Atreus are both, in fact, Gods, and nothing will change that. Kratos seeks nothing but redemption for himself and his name, and eventually, through perils and challenges, comes to terms with his and his son’s godhood, learns to trust others again, and most importantly - accepts that he once was the fearsome brutal God of War that rained destruction upon all, but is such no longer.

“Today, son. Today we will be better.”