Demon from afar - Kaori Yuki

Pinky swear--An imperial capital in an era of splendor and romanticism...Orphaned in an earthquake, Sorath is taken in by Baron Kamichika, the lord of 'Blood Blossom Manor.' There, he pledges eternal friendship with Garan, the Baron's heir, and Kiyora, Garan's fianc?e. But their friendship turns grisly by events none of them could foresee. The tender feelings each secretly harbors, the machinations of Baron Kamichika, and his strange and seductive female companion, and a fateful encounter with a young girl with bizarre powers...all draw them to the Walpurgis Night and the nightmare's climax!