Please sauce up your images, this is true art here.

I'm annoyed at the fact that I know this (trying to stop being an useless trivia sponge), I don't even play FE so why do I care? (It's cute, that's why)

ANYWAY, Artist is greatestjubilee, here's her Twitter, and she does sell those gremlins in physical form. Can't find the exact post, I guess someone else did this particular edit.

I know it because of this post. Thanks Sanakan_ht for sourcing it.