As a part of royalty, you must be protected out of harms way. That was Sakusa's job. He was your assigned knight to protect and guard you. If you were in your room, he stood gaurd at your door. If you were in the garden, he was at your side. Anywhere you went, he went.

You, on the other hand, were a spoiled and bratty royal who was the heir to the throne. You always gave Sakusa a hard time. Sakusa never will admit it, but he finds you annoying. Yet, he does his job