This picture just keeps generating ideas! For example: Sierra's motions in the second image remind me of what just happened over in the new story, "Yes, Sierra...". See the Christmas tree scene and ornaments for details....
I'm not sure about that logic. I actually had a discussion about this with a friend of mine in an old RP we did. Long story short (too late), his character's physiology was "magically retardant", meaning not only was he incapable of performing the art himself, but his body was born with a natural opposition to magic so strong that it actually repelled mana away from him. This protected him from transformations and the like (stuff that directly affected HIM), but we eventually realized that if you magically threw a rock at his character, it was still going to hit. Likewise, he was not immune to being frozen by the extreme temperatures caused by ice spells, being blown back by magical winds, or (as is relevant to this picture) being set on fire. Unless she's made of Orichalcum, I think Nana-bot's metal body would eventually melt under a strong enough fire spell.
Ah well. I won't detract from your work. The art is adorable as always, so I'll just attribute my perceived gap in sense to her still being a rookie magic user.
I'm with Ausdpr: I remember the Sierra story by Princess Pottypants and this does seem like an appropriate Epilogue! Or perhaps the Princess is using this image as the creative seed for a future story?