We knew it was coming. I mean, we had mostly Tsukasa's side of the story, focused on her work as an apothecary and how she became what she is now and mostly unaware of the romance between the Emperor and Kaguya and the drama unfolding (only hearing of it from rumors), told back in Volume 16. Now we're just getting more context on that romance and her unaware hand in its progression.
Now we see the Emperor commissioned her own father to make a new deerskin barrette for her as thanks for her help, unaware of her parentage. Perhaps if he knew the elixir was diverted to save the one that helped him, maybe he would have been more forgiving.
And yeah... it's clear this Kaguya learned what love was before being called back. We'll have to see how the modern-day incarnation also manages to comprehend love. She's certainly struggling, right now.