What we do know is that Sapphire, otherwise known as Sophia Dragan, is the Queen of it, Natalia is the Crown Princess of it, and that she has managed to persuade some very old souls from previous cycles of existence to be members of her court. Natalia actually visited the Ninth Abyss, invoking the diplomatic Rites, and departed again, taking Sister-Princess Ysolt, and Sacred-Prince Taranis, with her.
But, Who, What, Where, Why and How are all questions that remain unanswered at this time. And perhaps may never be answered by this author.
Princess Tarassin of the 9th Abyss
For those who are looking for potential contact with the 14th Abyss, rumor has it that Leo Taylor is acting as their Topside representative for certain classes of dealings. It even says so on at least some of his business cards, and one imagines it’d be a dangerous thing to claim if it weren’t true.