Huh. Interesting story. Still no idea why she got stronger after death.
I've seen stories like GUNNM where the impact of attacks is used to refine or motivate parts of artificial bodies, but I didn't catch anything like that. (Breaking the speed of sound while not moving)
Angels typically get stronger by taking in better materials which comes with having better mentality. I guess she "ate" the sword?
Thank you for doing this side project, but I really feels like it should have been another dozen chapters longer.