I have made an art pack containing the thumbnails, sketches, linearts and finished pages in full resolution! Plus the script/screenplay of the comic! It’s Pay What You Want, meaning you can get it for as low as $1! You can grab your copy here: https://gumroad.com/l/qqsWZ
Looks like it has something to do with the sun? Perhaps photosensitivity is believed to be bad omen or a sign of sinfulness, and exposure to sunlight is meant to expose it. Given the way others are dressed, it seems not to be about nakedness, but about maintaining a certain level of exposure to light.
Link
AndiGreyScale
Man this is fantastic! =)