User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-104.7.80.176-20150603035509/@comment-16281343-20150603042151

The part about her neck is from a questionnaire as already mentioned in that particular trivia.

Rias being afraid of camels is from the short story that is on the reference list of that page.

Reason:
 * Camels is a symbol of Gremory (See Gremory in Ars Goetia) . That's why the mascot for the Gremory is a Camel. (See picture of Sairaorg in an apple costume, the one behind him is wearing a Camel costume) . They also have a farm where they take care of camels near the main city.


 * When Rias was still small, she secretly went to the farm and was harmed by camels that has yet to be domesticated. And from that onward, she has a fear of camels.