Shikigami Monitor Recruitment
Looking to hire new shikigami monitors. Position offers the chance to gather info for newspaper articles, learn to use new technology, and much more. Requirements: Must be a beast youkai or have been one in the past.
As far as job recruitment adverts went, this one was pretty shady. Nobody gave it a second look... except for the usual tengu and kappa.
Summoning
It's a little-known fact that shikigami wait in a private room, only coming out when they are summoned. These rooms are spaces unbound by spacetime and truly provide private living quarters. Shikigami most certainly do not live in those colorful balls.
Shikigami never know when they'll be summoned, but when they are, it's not long before they're forcibly brought out into the world. It seems that a handy automatic outfit-changing function activates when required, for which the shikigami are grateful. So shikigami are always ready to work even if they're out or busy taking a bath.
(Wait...who'd be grateful for an outfit-changing function? And doesn't that last bit bring into question the "private" in "private room"?)
Heinous Lies
In truth, you can't always bring your memories from one parallel world to another. And in this case, you most certainly can't. So the job advert was lying when it said you could gather info for newspaper articles and learn to use new technology.
What a horrific lie to tell.
Kishin
Those who control shikigami mainly do so through programs known as "kishin," which just so happens to also be the name for the oni of Hell. This perhaps has some relation to shikigami occasionally being written as shiki-oni-gami.
Apparently, the more tails a shikigami has, the more powerful they are. Likening them to computers, their tails could be seen as their CPU, memory capacity, or SSDs. All of a sudden, Ran and Chen's tails seem like more than just cute features of theirs.
Yukari Yakumo's Whims
Yukari wanted to investigate parallel universes, and for that, she had to take special measures. While Yukari's undoubtedly a youkai, she's still a young girl at heart, and so she also wanted to have some fun. However, her idea of "fun" is somewhat deranged, with an example being making someone dinner simply to poison them. (Even a certain maid wouldn't go that far.)
Interpreting this recruitment attempt as an act of desperation, you can surely feel the love she put into cooking up her Yukarin Balls. Then again, perhaps you can't. It seems that without teaming up with Reimu, she can't perform at her best.