No, Serenity didn't kill me. It's the opposite rather, I was responsible for Serenity's death. My death was the result of my own actions, a price to be paid for what I did.

[Setsuna remained standing for a moment, looking at the cup of tea.]

We spoke several times actually, you just didn't realize that it was me. I helped you patrol and then kept the city safe from the threats that were lingering in the fog.