The HC Series (Latin: homo caedelius), also referred to as Killing Dolls or Mechanical Soldiers, was a type of cyborg created by the Vatican scientist Gepetto Garibaldi. The series was never mass-produced due to the failed insurrection of Garibaldi, who used the ten prototype cyborgs to rebel against the Vatican. As a result, eight of the ten prototypes were destroyed by the Vatican; the surviving two cyborgs—HC-IIX and HC-IIIX—were appropriated by the Department of Inquisition and the AX, respectively.
In 3036 AD, Professor Gepetto Garibaldi began formulating ideas for the creation of a series of cybernetic soldiers. With the initial support of the Vatican Papal State, Garibaldi initiated the Homo Caedelius Series—cyborgs, also referred to as "Killing Dolls," that were fully mechanical with the exception of their organic brains and brain stems. The program was ultimately terminated in 3055 AD, however, when the Vatican government declared the HC Series to be inhumane.
The HC Series had only produced ten prototypes by the time of its cancellation. As a result, the series never entered the mass-production stage. Nevertheless, the professor refused to accept the Vatican's decision, believing his creations to be works of art. He confiscated the prototypes and programmed them to serve as the soldiers of his rebellion against the Vatican.
By April 3054 AD the professor and his "killing dolls" seized control of the Castle of San Angelo in Rome, the capital of the Vatican Domain. The Vatican launched a counterattack to reclaim the castle; aiding the Vatican was Abel Nightroad, then a newly-ordained Catholic priest and close ally of Cardinal Caterina Sforza. During the fighting Nighroad defeated all ten cyborgs. With his insurrection ending in failure, Garibaldi committed suicide in order to avoid capture by the Vatican.
In the aftermath of the battle, Sforza and Nightroad confiscated HC-IIIX; the last operational model prior to the rebellion's defeat, the cyborg ultimately came into the service of the Ministry of Holy Affairs and its special department, the AX—both of which were administrated by Sforza. HC-IIIX was not the only unit to survive the failure of Garibaldi's rebellion, however. His "brother," HC-IIX was salvaged and reprogrammed as a member of the Department of Inquisition.
The following is a list of known models in the HC Series line:
- HC-IIX - Killing Doll, second prototype; renamed "Bartholomaios" and commonly referred to as "Brother Bartholomaios;" member of the Department of Inquisition.
- HC-IIIX - Killing Doll, third prototype; renamed "Hercules Tres Iqus," commonly referred to as "Tres Iqus," and codenamed "Gunslinger;" member of the Ministry of Holy Affairs and the AX division
- Eight prototypes - all destroyed by Abel Nightroad.