Horii was a character in I.L. arc who made a short appearance in Anime and Manga.
In both anime and manga, he killed Shu that made Ginji mad and tries to kill him. However, Ginji fainted. He laughed and said he will kill the Lightning Emperor for his self.In his laughter, he was later on killed by Akabane. In the manga, his hands were cut first by Akabane before he was killed.