No, Raiko is not the Angel in question, but who I'm refer here is Ritsuko Shinko, the Angel character I created based on Raiko (but still not Raiko anyway).

The new Craftsman of Heaven, Ritsuko is responsible to create all kinds of divine tools and weapons. Some of them are also sent down to Earth, as to use as liturgical vessels and relics (?).

As I said before, Mari's knives are not normal, they are divine tools crafted by an Angel from the Heavens, and Ritsuko is the one who crafted them. How do these knives work is a total mystery for the word of humans to speak out, and personally I have a brainf-ing moment when trying to realize how Mari's knives work.