Kasen's connection to the monkey's paw is her missing arm. It is important that she has an unfulfilled desire: to take back her arm, which makes her vulnerable to the temptation of anything that can fulfill wishes.
According to spoilers (I didn't mention this one), since the appearance of urban legends, Marisa has taken an interest in the rich legends surrounding schools.
Fair enough, either way it's going to be great to see Moe Harukawa do the artwork for the game, hopefully his portrait of Futo won't make her look 7 years old like in HM.
There
might be a reason to that. It is possible that Futo is literally a bratty teenager. That would explain her stupidity, cowardice and rashness very well.
Time for already simplified obscure knowledge: (
EDIT: also not entirely accurate)
The Mononobe clan is a priest clan. Ise Shrine, the shrine most important to the Japanese throne, is divided into the Inner Shrine for Amaterasu, and the Outer Shrine for the agriculture goddess Toyouke. In the Outer Shrine, there are girl priestesses, around 10 years old, called 物忌
monoimi "Abstinence", and there is one 大物忌
ohmonoimi "Great Abstinence", who is a Mononobe girl, responsible for offering food to the gods. The age of an
ohmonoimi generally ranges from 9 to 14 years, as she will be replaced by the time of her first menstruation. Afterwards, she will remain celibate for her whole life.
What may trip you up is that Ohmonoimi is also another name for Toyouke. This definition of the word is much more widespread on the internet by comparison. I have no idea if the priestess is supposed to be a proxy of Toyouke.
Futo's last spell card and Overdrive card in TD are called 聖童女「大物忌正餐」 and 聖童女「太陽神の贄」. Their accurate translations might be Sacred Virgin "Ohmonoimi's Dinner" and Sacred Virgin "Offering to Sun God". 聖童女 "sacred little girl" or "sacred virgin" is a phrase coined by a folklorist to describe the
ohmonoimi priestess. The "dinner" or "offering" itself refers to the Outer Shrine's daily ceremony of offering food to the gods, once in the morning, once in the evening.
In addition, Futo's dress is based on the
ohmonoimi garb. People have pointed out it seems to be her not entirely successful result of adapting to fashions of the modern world.
I can't find the place where I saw a photo of a real life Ohmonoimi girl, but Futo's NicoNico Encyclopedia
entry has a surprisingly good summary of related info. And here's the official Ise Shrine site on the
dinner of gods.