And they have very overactive imaginations.
- The second stage allows it to hurt anyone, including the user.
The fairies got bored sometime after the Grail War was dismantled, they decided to rub their ability to achieve the Third Magic in the faces of the Einzberns and the Mages Association, by creating their own version of the Holy Grail War.
- Keeping in mind the Creator Connection (at least for Fate/Zero), and the fact that the Butcherverse and Nasuverse probably have some overlap, you know Kyubey is also involved. Somehow.
- Incubators were created by some much more sadistic fairies, and they've obviously been doing it for a very long time. Some other fairies have called Dude, Not Funny! and tried to stop them, but unfortunately they aren't powerful enough stand up to the sadistic fairies. Sagami might be controlled by one of them.
The fairies can't completely erase all the fighter's memory of the war, so instead mask all of those memories as childhood delusions via Fake Memories. The better the rewrite is, the more negatively they react to them (ala Love, Chunibyo & Other Delusions).
Remember the Fairy War is supposed to be entertainment for the Fairies, when the Literature Club got their powers and no battles happened, in part because of Kiryuu, the Fairies were disappointed. Hoping to introduce some conflict, they awakened Mirei's Grateful Robber to get at least one battle out of them. They were disappointed again when instead despite a brief confrontation they became friends instead.
- Jossed. Dark and Dark in the End is a flame that can never stop burning. They made him promise not to use it ever again for HIS OWN protectoin
Whenever, Andou activates Dark and Dark, it's always with his right hand. If he concentrates he could ignite the flame any where really, if he would just stop playing to his own chuuni narrative of the "hellfire of purgatory sleeping in his right arm".
This theory is based on the theory that in both series, the supernatural element is caused by an acute case of Unreliable Narrator.
Chifuyu is Yuki, she is a genius but still has trouble distinguishing reality from imagination and understanding adult emotions.
Jurai is Kyon, obviously, obsessed with pseudo-science trivia and supernatural events.
Mirei, the outsider girl who constantly steals people's powers, friends and eventually club room, is Haruhi.
Tomoyo, with time manipulation powers but who can not (yet) go back to the past, is Mikuru.
Hatoko is Kyon's sister. Her control over elements is limited to "the waterworks", salty water from the eyes, but this is plenty enough to control an elder sibling and his friends when parents are around.
Sayumi, I am not really sure, possibly Tsuruya.
Kiryu, the boy from another part of town who is everything better than Jurai, is Itsuki. Actually, he is an alternate version of Jurai/Kyon himself.
Kuki is Ryoko.