The Unfortunate Messenger and the Unreserved Emperor

Julius is a messenger from the Litruius Kingdom, he has come as a messenger to declare war on the Serian Kingdom. However he is actually someone from the 21st century, and this is the world of the book 'The Cold Emperor Is Not So Cold.' The story of which the female lead, the princess of the Litruius Kingdom, is forced to marry Cedric Olcilius, who is the male lead, and later on the female lead will fall in love with Cedric and blah blah blah happy ending. And he is the character of which appears in chapter and gets his head chopped off and begged for mercy to showcase the 'tyranny' of the male lead. However for someone who's about to get their head chopped off Julius doesn't seem to care at all....