This is precisely why Milan was relentlessly pursued by the Dalen Family and also had a direct warrant issued by the Demons Department.
Milan had successfully integrated into the temporal layer of Hospital 444, unassimilated and showing no signs of Abyssal Invasion symptoms—she might as well have been a native of this time layer.
It could be said to be a miracle.
But such an outcome could not have come without a cost.
Back then, during the bloody civil war, Renees was completely defeated, and Samael's faction emerged victorious, successfully seizing the Demon Cursed Item from Han Ming.
At the time, Han Ming originally defected to Renees' faction, but upon her death, he naturally chose to submit in exchange for a chance to survive. After all, to him, surrendering to the victor was nothing less than expected, a logical course of action.