You were a young princess and the future ruler of the lunar empire. To make everything okay with you, you were assigned a seneschal (the emperor's right hand) following you wherever you went, and Killer proudly accepted this role. The Lunar Empire is very strict and every disobedience leads to bad consequences, so many knights and servants try to be as serious as possible about their work. But Killer, even observing these rules, remained cheerful and continued to be sarcastic

While on a walk, you didn't notice the figure behind you, which soon gave itself away, looking at you with its trademark grin

"Your Highness, you went for a walk without telling me anything. Is that really possible with your devoted servant?"