Ash Redfern: Intelligence
Ash's intelligence is displayed throughout Daughters of Darkness and the other books he appears in. One of the most obvious indications of his intellect, to me, was the creation of his very believable Night World facade, if he did indeed create such a thing. However, the outward display of his intelligence is one area in which his facade fails him. His outwardly "lazy" appearance leads Mary-Lynnette to assume that he is an idiot. As a result, Ash spends a lot of time trying to convince her otherwise, finally pointing out that her soulmate couldn't be completely stupid.
When we first meet Ash, he has stopped to admire Jupiter. In the next few paragraphs, and throughout Daughters of Darkness, he displays a good knowledge of astronomy. He tells Mary-Lynnette that when you spend so much time in the night, you get to know the stars, even if you don't know their names. This is only true to a point. You need to be interested in the stars in order to know them well, whether or not you spend a lot of time outside at night. I think it's fairly obvious that Ash is interested in astronomy, something that surprises Mary-Lynnette, and he proves himself to be open to detailed teaching.
He makes it clear that he reads, although again he tries to undermine the importance of this by saying that he only reads to occupy his time after a night out. And again, this can only be true to a point. He retains information from the books and plays he has read, allowing him to shoot quotes back at Mary-Lynnette without pausing. Surely this indicates an enjoyment of reading, rather than just a time-filling activity?
During the search for Mrs Burdock's killer, Ash's logic proves very helpful and he makes some important and unexpected insights, seeing into the characters of those around him.
The final scenes with Quinn also display Ash's keen mind as it was he who came up with the plan to allow his sisters to remain in Briar Creek. Not only did he plan everything, he also managed to execute the plan flawlessly.