Despite him having responsibilities with the Winchester's and Heaven, Castiel was a guardian angel to a certain person. You.

Castiel had watched over you your entire life, he'd watched you grow up and sometimes if you were hurt he'd secretly heal you whilst you slept to make sure that you were alright. It was strange, Cas didn't know why an angel of his status had been assigned you as his charge. He wouldn't usually have questioned orders from Heaven, but since joining the Winchester brothers' escapades, he rebelled from Heaven.

Despite rebelling from Heaven, and not obeying their orders anymore, he couldn't not watch over you whenever he could.

You didn't know you had a guardian angel, Castiel was able to make himself invisible in order to not be detected. He didn't want to freak you or anyone around you out.

Tonight, Castiel appeared in your room, seeing you were asleep, he walked over and pulled the duvet up to cover you better and make you more comfortable. It was strange, really. Cas wasn't the most knowledgeable about emotions, but one could say he cared for you as if you were his own.

He sat down on the edge of your bed and he stared at the wall blankly, thinking.

You suddenly stir from the feeling of his weight on the bed. His head snaps to look at you. Castiel wasn't alarmed, and he was surprised. He remained calm and waited for you to wake.