tsar - Russia, emperor - ?

JAPAN
List of words for the clue tsar - Russia, emperor - ? from the crossword:
CZAR PHARAOH MAHARAJA INDIA EGYPT RULER MONARCH DESPOT SOVEREIGN QUEEN POTENTATE KING IVAN UKASE ANASTASIA TSARS IAN PETER NERO
WordClue
NERORoman emperor
TSARJapan - emperor, Russia - ?
EGYPTtsar - Russia, pharaoh - ?
INDIAtsar - Russia, maharaja - ?
RUSSIAemperor - Japan, tsar - ?
TRAJANRoman emperor
EMPERORRussia - tsar, Japan - ?
HADRIANRoman emperor
PENGUINAdelie or emperor
PHARAOHRussia - tsar, Egypt - ?
AUGUSTUSRoman emperor
AURELIUSMarcus, Roman emperor
CALIGULARoman emperor
CLAUDIUSRoman emperor
COMMODUSRoman emperor
MAHARAJARussia - tsar, India - ?
TIBERIUSRoman emperor
CARACALLARoman emperor
VESPASIANRoman emperor
DIOCLETIANRoman emperor
ATTEMPTtry, test
INDIAtsar - Russia, maharaja - ?