Metal guitar virtuoso, Xander Demos has topped the Hit-Tracks Top 100 chart with “Under A Darkened Sky,” one of two vocal tracks from his debut album, Guitarcadia. The song took 13 weeks to ascend to the top, besting Top 10 releases by Mumford and Sons, Kings Of Leon, Bonamassa and Earth, Wind and Fire. “Under A Darkened Sky” is an …