Clevatess: The King of Dark Beasts, the Baby, and the Undead Hero

He killed the heroes, killed the king, the devil beast then found the "baby of fate"... Having both superior intellect and destructive power, such is Clevatess, the devil beast king. Angered by the 13 heroes' attempt to take his life, he had decided to bring ruin upon humanity, but he gets entrusted with an unexpected nuisance: a newborn human baby. Is this the tale of a world close to apocalypse or a diary of new-era childcare?