The Apostles (使徒 Shito) are a group of indoctrinated men who were the unwitting slaves of Spinner Superior; there can be up to fifteen of them at one time, and they all possess dangerously low life-force values. It's unknown what has happened to the Apostles as of Spinner's death.
Apostles are seemingly infected with a type of Spinner's insects, leading to eerie insect-like sounds being emitted at random, and the ability to undergo a type of metamorphosis which allows more insect appendages to grotesquely protrude from their body; the latter is only accessed when they sustain a certain amount of damage. Even when they are seemingly dead, the insect can detach itself from its host body, and attack on its own – the insect itself is roughly the size of a human's head. Although unknown, when a male becomes an Apostle, their personality seemingly changes, becoming far more aggressive.
Spinner created the Apostles in order to gather souls to be used to in the creation of a special type of bug. However, the bugs controlling the Apostles were frequently destroyed, leading to Spinner eventually abandoning the project and using Saya Terumi for collecting them instead.
One of the first Apostles appeared in the beginning of BlazBlue: Bloodedge Experience — Part 1, where he chased Raquel Alucard down the streets of New Kawahama City, the two eventually met and fought in the Restricted Ward of the city and the Apostle nearly won until the fight was interrupted by Naoto Kurogane. Despite losing, the Apostle managed to take the young man's arm.
Of all the Apostles, Tadayuki Isa is the most notable of them all, being the only named one. He managed to take on both Raquel and Naoto for a short period of time, but he was unable to stand up against the latter's newly awakened Drive. Thankfully for Tadayuki, he was saved by the Mitsurugi Agency and a lifesaving operation removed the insect from his body.