I discovered this song on Cytus, a famous music game for iOS. Even though I'm not a big fan of Vocaloid songs, COMA was somehow an exception for me. I purchesed this song to help the artists no matter if it's free-to-listen on the internet. My biggest decisive factor for buying it is ensou's blog article.
ensouensou.tumblr.com/post/96344620928/message-please-read 
