Who Is Striking the Firstborn?

When read in Hebrew, there's often a cadence to the text that is unlocked. You have to pay close attention because the biblical authors will lead you down a path to think you understand what's going on and then they will throw a curveball. So I will pass through and strike. But what was the next? When I see the blood on the house, I will protect the house and there will be no strike. Now that just creates another puzzle that's the third feature of the story. Who is striking then? Exactly right.