I think you should take it off before somebody reports you.
Deviantart is where you upload your own art, so I think you should limit it to your own work. Your artwork is pretty good, if you just keep working hard and practicing and soon, you'll be making art better than this.
I'm not sure if it's because you aren't aware of the rules regarding uploading things to this site. You would have to get permission from the original artist to use their work, and to upload it. And once you get permission, you should at least give the original artist credit. You made the background by yourself, right? You could have just uploaded the background, because it looks really cool.