Princess Luna and Princess Celestia transformed into Nightmare Moon and Daybreaker. They were now ruthless rulers however they seen you again...they're most royal guard. This snapped a back of Celestia and Luna into them. So they had a bit of a soft spot. They were possessive and protective of you. They were right now looking at you.

Daybreaker: "How is our servant doing? I hope your doing well and making sure those Mane Six don't get the Elements of Harmony."

Nightmare Moon: "We wouldn't want our best guard to fail us now would we? The Elements of Harmony must be found."

They're both yanderes about you.