"マンドラを食すミスラ。なぜ裸なのかは謎。ムッキムキでごめんなさい。" - mithra

I bet they taste like turnips.

As I said before, the translation request is on the artist's commentary, not the picture.

"A mithra eating a mandora. Why she is naked is a mystery. Please pardon the heavy build." - mithra

Theory: She doesn't want to get her clothes dirty.