I think that for supports Demonic is a little too expensive and doesn't offer enough utility. The focus of the build is to build 2 AP items total one of which being Cosmic Drive, because i want to do this efficiently i believe Demonic isn't a good fit for supports. its passive is mostly damage focused as well and that is not your role as Shen support. For Top or Jungle it could definitely be worth trying out although you will need 2 adaptive force runes to activate Cosmic Drive.