King Leonidas vs Agent Ward...

King Leonidas takes on Agent Ward in a fight to the Death or KO with no BFR allowed...

Pure Hand to Hand combat only...

Who wins?

Probably Ward. The Spartans were trained to be stone-cold killers, using their weapons as efficiently as possible, not subdue their opponents by grappling with them. Ward would have far more extensive unarmed combat training and experience than Leonidas.

Yeah, Ward has way more h2h combat feats, usually against better opponents than Leonidas has faced (in h2h anyway). Put a sword in their hands and it would be different.

Leonidas literally has virtually zero pure H2H feats. Ward has several, including feats against enhanced opponents. He wins.

Been sometime since I've seen 300, but wasn't there a scene early in the film of Leonidas grappling with another Spartan? If so, this likely means he's trained in pankration, which would make sense as the Spartans (and iirc all other Greek cities) did train themselves in it to be better soldiers, they even tossed out the few rules the sport had like no jabs to the eye or testicle grabbing, cos rules are for pansies.

Granted, I'd still go with Ward who is a highly trained/skilled assassin in a H2H match