User blog comment:Sinister 00/About 666/@comment-117.193.172.96-20140220065957/@comment-1359322-20140220070401

Nah Mil-Tan is 666, 666 is in fact 666 Mil-tans, in the past God attempted to seal all of them but only sealed 660, and 6 of them escaped. One of them is the Mil-tan that is Issei's client.