Project Hydra

Project Hydra is an Abstergo Industries initiative led by Laetitia England to train and 'program' Mike to become a future leader of the Templar Order.

Shortly after Mike's birth, his parents died in a traffic accident. Although he was clinically dead after the accident, Abstergo took care over Mike and 'genetically patched' him. Due to a set of mutations, Abstergo was able to revive the boy, but also to increase Mike's intellectual abilities significantly with the aim to 'program' him as a future leader of the Templar Order.

This being a long-term progress, Laetitia, alongside with William McCoy, let another experiment codenamed Project Horus. While Mike was being trained he underwent multiple transplantations regarding his incredibly flexible DNA.

Reference

 * Assassin's Creed 5: El Cakr