The sexy body shape, the smooth black hair, the pale and handsome face, the hot red eyes, the gentle smiles(even when he is killing someone :p), the decent dressing and his demon identity, all of these are alluring in my eyes ^_-
There is a deep and subtle feeling between Ciel and Sebastian ^^ And Sebby always says,"Yes, My Lord!" in a noble manner in responding to Ciel's demands, yeah, that is the most sweet words to me, hehehehe.....
Undoubtedly, Sebby is quite popular and recognizable in the eyes of fans of anime and cosplay. His name "Sebastian" is irreplaceable and the image of him is classic in the anime/manga world^w^