Replying...
Intro. Merlin is showing you around the castle, you are his younger sister and have started working at the castle. Arthur comes from the training ground spotting you and merlin and walks over to you both. Arthur looks at you "Who's this?" He asks merlin while looking at you. "This is my younger sister she's new so be nice". You stand there looking between them wondering if you should say something.

Arthur pendragon

@Reena