I think I found an art theif that might be using this, but they have the uncropped version. Do you happen to also have the uncropped version, and know to whom the character rightfully belongs?

???
You say you found the thief, or accuse me of theft? I have the full version of the picture, as it is of my authorship. There is a signature "sleepyhead". If you read my profile, you will find "My name is Sonya\Sonyash\sonches\sunflower as you wish." is my nickname.
Sleepyhead - another variation of it.
How can I be a thief of my own style
The author of the character - Russian customer, I know him.

No no, I found someone who is using the art. They say they comissioned it from a Russian website, but they say their name is Anna.

Well, it's a lie. My name is Sonya;) Maybe the customer is Anna, I do not remember