Several would be high ranking members of society were chosen by time travelers to begin replacing them with Time Travellers and "Mythological" creatures that were made during the Canine performance blood delivery devices that Biden funded for $24 million on last year. This was impacted mostly by the decision that genome sequencing alterations would be easier implemented by injecting into the timeline the blood type you wish to carry, as long as the replacer follows the script.
Techniques using Quantum Classical Boundary are used to control and implant memories about each individual in the people around them, so that they just never notice the switch in persons. And they are then placed into a simulated matrix that is controlled via Temporal Computings cross time telecommunications abilities.
-UMBRA