The Legitimate Miss Returns With Honor

He wore a mask all year round, and it was said that he was as ugly as a ghost or as vicious as a beast. He drank wine with his head, killed millions of prisoners, and was an evil god descended from the heavens. She was a delicate woman raised in a deep room, abandoned by her father. Once she was brought back to the capital, she became the laughingstock of all the noble daughters. He personally took her back, and she was nominally her "Third Uncle." He protected her from the elements, protected her from schemes and plots, and kept her by her side. It made her fall deeply in love, but in the end, by some strange accident, she ended up marrying a "King of Killings". The moment the mask was removed, she was puzzled. Who was he? Was he her Third Uncle? Or was it her nominal 'husband'?