you know what? I think I get it. I mean I understand why Luke reappears.First, his soul/spirit fusionned with the "dead" Ash' corpse. Second, he's the perfect isofon of Lorelei, right? So when Tear sang the song (i forget what's the name exactly), well you know the song composed of 7 parts/artes, she called Lorelei -so, Luke. That's why he reappears.