All right. I've been a bit out of the loop in regard to Atryl/Siden's work, but and as far as I can tell, they often work together on Siden's drawings. In addition, they both have an extremely similar art style(One I personally couldn't tell apart if not for the signature [which also usually has Atryl's Tumblr in it]). I went on the Atrylplus Tumblr and also found that Siden shares the site with Atryl. The two seem almost synonymous in their art, so I pose the question: On posts done by Siden, should we tag both Siden and Atryl?
Updated by SnowWolf