Therion have premiered a new video for their new song “Tuonela.” The track, which features Marko Hietala (ex-Nightwish), appears on the band’s new album “Leviathan,” which was released today (January 22). Christofer Johnsson commented: “Like everyone else, I’m very sad and was also surprised to read that Marko is leaving Nightwish. But I understand the…