Crimson Red goes well with Ocean Blue

In a Kingdom far far away, there was a Prince who's known as the Sadist Prince. No one dared to get on his way whenever he wants something until she came, her eyes reminds him of the Ocean that whenever he stare at them he felt like drowning, scary yet addicting. But what will happen if one day she needs to go? Will he use his power to let her stay? Or will he let her go despite his powers as a prince?