Hey, um,
@TheOriginalBuss I know it's like a year late, but...
"Heika" is gender neutral; always, always will be (even with Hisahito-sama reaching adulthood), and in English the TL would say
"Their majesty"
... and you would not say "his/her majesty" in English, unless you say "Her Imperial Majesty."
It's only ever "Their Majesty" or "Her Imperial Majesty" when using the third and first person address.
Pg7: Panel 2, Bubble 2 made me think of this.
This kind of English to Japanese is fun; sometimes crazy, but very fun