Most of the Japanese population are non-religious, but they still celebrate different holidays and rituals from Shinto, Buddhism, and Christianity. Much like atheists still celebrating Christmas, Easter, etc. Christianity is appealing to the Japanese because it has so many symbols and images that represent the religion (the cross, Mary[Maria], angels, etc).
So, I highly doubt Ayu is christian/catholic/etc, it really makes no difference to me and won't change how I look at her.
|