Board Thread:Fan Fiction/@comment-5847295-20121211110816/@comment-5674726-20150913123045

Merlin would be a Slytherin. He is very ambitious and it took a lot of cunning to be able to repeatedly save the day while staying under the radar.

Arthur could be either a Hufflepuff or a Gryffindor, although I lean towards the former. He was brave but he was also very loyal to his friends and very conscious of his duty to his kingdom so I could see the Sorting Hat placing him in Hufflepuff.

Morgana, I could see being Sorted into Gryffindor. When we meet her, she is quick to speak out against Uther when she disagrees with him, heedless of the consequences, and even in her later years, her plans tend to be reckless and ill thought-out. She is ambitious from Season Three onwards but lacks the calm cunning of a Slytherin. Morgause, on the other hand, would be a Slytherin.

Guinevere would be a Hufflepuff. She's loyal, a hard worker and, while there is some ambition there, I don't think that it'd be enough for Slytherin.