Daemonhosts are created when daemonic spirits are bound to the flesh of human beings, allowing them to hijack the individual's soul and giving them control over the victim. Within this union, the daemon acts like software, using the body like a puppet, and the individual is the hardware being made to perform actions. The problem is that the software's output can only be as good as the hardware's capability. This is similar to installing Windows 10 on an old system running XP: It would barely work, suffering numerous problems and returning lackluster performance. The soul of an adult human is structurally solid and no longer as malleable, and eventually leads to an obsolescence where the body decays and disintegrates from the daemonic aura poring from them. The only solution to this problem is to build a human body from scratch that is specifically designed to contain a daemon's power.
The Nazi project known as Lebensborn was a state sopported association in Germany created by HYDRA, an occultist subgroup under the Schutzstaffel, with the stated goal of producing future proud members of the Aryan race. White, blond-haired and blue-eyed, These children would be tomorrow's leaders of the glorious Third Reich as true manifestations of Hitler's master race. In truth however, these children were meant to serve as perfect subjects for daemonic possession. A specific daemon would implant a portion of his aura into the developing soul of the child. This energy would manipulate the soul while it is more malleable and less structured, making it perfectly compatible to suit the daemon. This would allow for a perfect daemonhost that the spirit could permanently inhabit without fear. When the child grows into a young adult, the possession ritual would take place in which the daemon would bond with the host to take control. "Heil, mein Führer!
However, the Nazi's master race of a super soldier army of daemons backfired in a mysterious way. It was discovered that these possessions left the daemon subject to the individual! The daemon was now a slave to the human that it inhabited, allowing the possessed to use the daemon's power as it was his own and denying the spirit the control that it wanted. Ironically, making a soul compatible with a daemon will ultimately reverse the traditional system of control, as opposed to an incompatible victim. These spoiled brats, thinking themselves above their masters, have refused to swear their allegiance to the great Fuhrer and have risen up to take power for themselves, putting the future of the Reich into question!
How could a Nazi program to create demonically possessed children go horribly awry?