If any of you non-novel-readers are unaware of what the Kiharas are, I guess I can go over in some detail. There's been a few in the anime and manga, but I don't think any of them have really gone into what exactly the Kiharas are and what they represent. They've been around since the Academy City Invasion arc, but I don't think they were properly realized as a concept until the currently unanimated Baggage City arc.
The Kiharas are a very large family of scientific researchers (there's around 5000), mostly living within Academy city. Though they are more akin to a mind virus than a family, however they are all apparently of a single bloodline. They are all very VERY intelligent, to the point that it is ludicrous. They are scientifically brilliant in a variety of bizarre and advanced fields, many being leading specialists, as a result many hold positions of power in academy city (however none seem to be on the Board of directors). And, most of all, they are all pure evil. They represent the very worst of the Science Side, completely lacking morality, respect for life, and any concept of limitation on what they can or should do. And worst of all, they feel attracted towards doing things in the worst and most destructive ways possible.
In all of Toaru, where most villains are given some sort of sympathetic motive, the Kiharas are a major exception. They seriously are just evil for evil's sake, and on top of that being evil by nature, not nurture. Kiharas are probably the most dangerous individuals in the entire Science side. Just a single one is an incredible threat if they put their mind to it. If Board Chairman Aleister didn't have them on a leash, they'd spread into the world like a cancer and wreck everything.
All you need to know about this Kihara Yuiitsu without spoiling too much of New Testament, is that she is an important character in NT, being introduced in NT4. She's more of a stringpuller and less direct than most of her family at this point in the story, however with her involved there is a big chance multiple other Kiharas are involved as well. We already know Noukan is involved.
That being said, this has officially left the scale of something Shoukuhou and co. can deal with. Kiharas are in a way the natural predators of espers, from a scientific point of view, in the way that lab mice are the prey of researchers.
TLDR: The Kiharas are a scary family of mad scientists on crack. One is a talking golden retriever who smokes cigars and has a mech.