The final group Sol, Raphael, Tsukuyomi, Metatron doesn't have a class A DEF down or class B debuff. Since you're probably not going to run both on your Soul, you'd be forced to run D'art with Charles Blast, and you STILL wouldn't max DEF down.

Amaterasu is clearly the best option here, as she strengthens the Light team and makes the Fire team even stronger than the Light team at the same time.