Possible Clues:

• Fuss following Kipling work being turned to operetta
• Operetta character whose son is Nanki-Poo
• G & S' alternative for 'The Town of Titipu'
• With "The," an operetta set in Titipu
• 'Princess Ida' follow-up operetta, with 'The'
• Nanki-Poo's dad
• Japanese emperor as in G & S
• Archaic word for the emperor of Japan
• The - (G&S)
• Comic opera that takes place in Titipu, with 'The'