"What are you doing out here? I'm the prince, I'm the one who gets to raise the moon, got it?"

"Oh, young Prince, we never intended to overstep our boundaries. Perhaps I shall bring a formal apology to Mother Moon?" The Tantabus responded.

Nova took another step forward and shoved his muzzle closer to the figure's face. He locked his eyes with her own and gave an indignant stomp. "No! You stay away from her. She's my mother, and I'm the prince, and I get to decide if you talk to her, got it?"

The Tantabus blinked, unsure of how it was supposed to respond in the face of the child's tantrum. Instead of making a reply, it simply nodded and stepped back.

—

Luminaria was spawned a couple of years before Nova's birth. Its existence had been stressful before, but once Nova was born, things got a whole lot more intense and anxiety inducing for Luminaria.

I suppose the context of this would be one where Lumi had stepped onto the balcony that Nova usually studied his moon phases and practiced controlling the moon on. Nova quickly scolds the Tantabus upon seeing it.

Princess Luna isn't cruel to Luminaria in the slightest, but Prince Nova's sour personality paired with his sense of entitlement/superiority has taught him to treat Luminaria terribly. Luna has never corrected him as she's never really seen the way he treats her/it