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Can I use the works which I find on deviantART?
DeviantART possesses no ownership claim in any submission and cannot grant you any license or permission for use, only the artist may do so.
All original works found in the deviantART galleries are the copyrighted property of the submitting artist. If you want to use a work you will need to ask permission from the artist, who is free to set whatever terms and conditions they wish. You should always ask permission before using any work which was created by another artist.
To contact a member of deviantART, you may use whatever contact information the artist may have provided on their profile page, or you may send a personal note to the artist if you have your own deviantART account.
Stock submissions and certain submissions marked with a Creative Commons License already have certain terms and conditions attached and can be used without directly contacting the artist providing that you obey the rules set for each work (which may vary from work to work and from artist to artist).