The Adam and Eve Project is the race created by Karlheinz.
According to Ruki's history, the plan details a human girl "Eve" with the heart of the demon lord’s daughter. "Eve’s" blood would choose an “Adam” who would be able to obtain the power to control the world, and their descendants would change the world.
In order to create this race, Karlheinz decided to mix his blood with the blood of a First Blood woman.
If this project is successful, the last stage of the experiment would be enacted: the destruction of the demon kind and the creation of a new race; one that felt and thought like mortal humans, but could use magic and the supernatural like the demon race. If not, Karlheinz will dispose of any failed experiment by himself, even if they're his own sons.
In lost Eden common prologue, where Karlheinz and Socrates talking about the project, it reveals that this plan exists in order to rebirth the dirtied world through the hands of "Adam". For that, the power of the World Tree, that is, the existence of the power of "Adam" and Eden is necessary.