You don't, your body does.

You stop and think as he rushes towards you, sword held overhead. How are you going to handle this? Should you try to talk him down? Beat him up? How can you fight him, given your lack of combat experience?

Luckily, your new body saves you from yourself. As he brings the sword down, you instinctually step out of the way, and then before you've even realised what's happening, you've punched him in the face, grabbed his sword out of his hands while he was reeling from the blow, and sent him sprawling across the ground with a backhand blow to the throat.

You look at the new situation. He's slowly getting up off the ground, blood streaming from his mouth, muddying the ochre on his jaw. You're holding his sword firmly, raised above your head to cut down in attack or defence.

He gets to his feet and rushes you again, screaming. This time you have the sense to let your body act, and act it does: you sidestep this charge as well, and bring the sword down in a slashing arc that opens the side of his face and nearly takes his eye out.

He collapses to his knees, one hand pressed over the cut. "I-I submit." He says weakly. He reaches down with one hand, frees his other sword, and kicks it back to you.

You're left holding a drawn sword, with the former warlord on his knees before you and the populance cheering for you. There's really nothing stopping you from killing him, and preventing him from posing a problem later, except perhaps personal morality. But since when has that stopped a strategy gamer?