In the beginning, the gods were actually some aholes... After the war for the title "Godde of Goddes", Marduk commissions the Human Project, starting with Lilith and Adam in Africa via The Garden of Eden. They are charged with creating enough humans to produce the worship he needs to secure his power. Lilith is given a choice: to either be replaced and die or procreate with Adam. She is loyal to her god but Adam is literally the first ever "nice guy". She cannot become part of the Echelon because of what happens when goddes and humans mate. She's reluctant to mate with Adam, who seems like the most boring lay ever. Lilith just wants to make a free choice.
No one ever counted on her forging a third path and messing up everyone's carefully laid plans.
Lilith.