Reception of the series has been generally positive. In his review of volume one, Carlo Santos of Anime News Network said that certain plot points "come out of nowhere" and the story was kept from its full potential due to finding some points like the designs generic. However, he enjoyed the series' quick-moving plot, exposition, and backstory. Sheena McNeil from Sequentialtart called it the best manga from 2006 based on its story and cast. A.E. Sparrow of IGN also reviewed the first volume, comparing the series' antagonist to three of "Batman"s villains due to his likeability despite his role. Sparrow also enjoyed Allen's characterization based on his tragic backstory. Calling the early volumes an "amateur comic", reviewer Leroy Douresseaux of Coolstreak Cartoons noted that the plot and art improved significantly with each volume, whereas "Otaku USA" was amazed by the amount of different element such as horror, scifi, fantasy, among others to the point of making it an atypical manga from its genre. Ross Liversidge of the UK Anime Network enjoyed the first three volumes; Hoshino had "an excellent quality of storytelling" in juggling dark plot, light comedy and appealing characters. According to Brian Henson of Mania Beyond Entertainment, the series became better over time; although some elements seemed derivative, it developed a unique identity. Yussif Osman of Japanator said that the characters were some of the deepest seen in "shōnen" manga, citing Lavi's backstory and the Noah Family.