Mundus wanted to break the seal and free himself. he decided to take Vergils blood from the night in the grave yard to use it to create a vessel for himself because what better than the blood of the demon that defeated you? not only would the process increase his own power but having the blood of Sparda would allow him to break the seal. The only problem is that the power of the human soul is strong and the resulting vessel came to be as a human would, with less demon in him than the Sons of Sparda themselves. an infants body would be useless to him, and by the time the body matured the seal would be weak enough to be opened without him. viewing the project a failure he ordered the baby be killed. however the minion was an associate of Sparda, though he didnt really care whether humans lived or died, he personally didnt want to kill any of them, so he dropped the baby into the human world.