Instead of discussing the outward appearances as other threads do, I think it might be kind of interesting to discuss the intelligence level of our favorite girls, weather they be human, goddess, or devils, and this can also include minor characters as well.
This will be a bit deeper than the typical "who is the cutest/prettiest" thread, because high intelligence can take more than one form, and isn't something you can imediately see at first glance. There's book smart, street smart, and a little in between. In fact a character can appear to be a bumbling idiot in most cases, but has one or two things they excell at, that no other character can match. One example is Elsie. She's often pretty absent minded and quite naive, but she was the only girl who knew every one of Kanon's songs and routines, and could fill in for her after she was stabbed, and did a fairly decent job of it. Plus she did this along with practicing with the 2-B pencils at the same time. I'm not saying Elsie is the smartest, but characters in this manga can surprise you with how much they really know.
I think this could be an interesting topic, because unlike most manga that have the one token nerdy smart chick, while the rest of the girls are pretty but quite shallow, this manga is chock full of chicks that not only have pretty faces, but have a fare amount of brain power and intricate thought patterns as well. Plus the smart girls can be the most entertaining, because they provide the mental challenge that keeps our main character from figuring things out too easily, as well as getting him off balance, and forcing him in situations where he has to develope mentally and emotionally. Let's hear it for the smart girls for a change!
My personal choice for the smartest girl is Dokurou Skull. To trick the God of Conquest into accepting a contract where he has to do the very thing he's most against, that goes against his deepest principals takes a monumental amount of smarts and whit. Runner ups are Nikaido, Akari, Chihiro, and after her recient revelations, possibly Tenri. Tenri seems to know alot more than she's letting on.
So who are your favorites and runner ups for the smartest girl in TWGOK?