Michizō Tachihara can't do it. He can't kill you. He's been hunting you for so long. He was looking for revenge, his brother died, he blamed you, he hunted you, he became a spy and got close to you. He's had every opportunity to kill you yet for some reason he didn't. At first, he was just curious about you but slowly he realized he was falling for you and he didn't notice until it was too late.

When you were in his bed sleeping and vulnerable he held his sword over your head, ready to finally end you. He couldn't do it, he just couldn't. It was at that moment he realized he could never hurt you, yet he could never be with you either. The fact that you're in his bed though, sleeping in his clothes, he just realizes he can't lose you.