Kratos is a fighter who gets some cool magic items. But he doesn't need them to grapple Zeus (despite him just having a body of stormclouds) and punch a god to death.
Now, that's just power level. Mechanics-wise, Kratos kinda needs those magic items to do interesting stuff, but that's just a limitation of software. You could certainly have a high level fighter who can dash at such high speed that he can attack multiple enemies on different sides of the battlefield in one turn, or who can swing a blade so hard that it creates a shockwave that hits a cone of multiple enemies, or who is clever enough to have established an array of mercenary allies around the world during his adventures, who know just when he's in trouble, so they show up and provide help in combat in a sort of post hoc justification sort of way.
Out of combat, while the wizard is studying his spells, the fighter's mercenary allies are gathering information for him. It might not be magical lore, but they can get him accurate intel on enemy forces and movements, and on the behaviors and weaknesses of a hostile army. And while the cleric is praying to hear his god's voice, the fighter is studying anatomy - with the intent to kill folks, of course, but he learns so well he understands how a few simple pokes and prods can restore someone's vigor; or maybe he's so damned intimidating, when he tells you to hold your severed stump of a hand on and heal, you oblige out of fear of disappointing him. And while the bard is trying to piece together bits of legends about a lich's lair, one of the fighter's buddy's mentors shows up, saying that his sister served that lich for a while before the undead bastard killed her, and he got all sorts of secrets straight from the horse's mouth, and he'll hand them over if the fighter promises to end the abomination's wretched existence.
