Since the title had to be translated, why choose 'Emperor'?
Hi! This question has come up a few times. There's always room for more info, but you may be interested in checking out some of the answers so far:
Why is the translation of Japan's monarch 'Emperor' instead of 'King'? - featuring /u/ParkSungJun
Who were Emperors and who were Kings? - featuring /u/redwhiskeredbubul and /u/dismaldreamer
What is the difference between a king and an emperor? Why were there empires in Rome, Japan, and China, but kingdoms in Africa and Europe? - featuring /u/Angiras