アレ(that) is a euphemistic expression implying negative meaning.
In this conversation, it means insane, wrong , idiot and so on.
Ueno : Which person is “アレ”?
Yamashita : Both of you.
P.S.)
The reason why they said same phrase ... is hard to put into words.😣
In japan, there is a humor with wordy...
Thanks for your hard work!
I guess red means color of Nishihara's underwear.
When Ueno asked her to wear something to cover her underwear, then Nishihara sensed what Ueno was thinking.
But Nishihara carelessly said that she matched red underwear set.
3枚 ( three flat things ) are panty, skirt, and petticoat.
It seems Ueno often wears this set. ( chap 24 N-Allnew Cloth )
sometimes 2枚 because of no panty.😊
カニの左手あくまで右手(kani no hidarite akuma de migite) is a play on words.🤣
Original title of this book is 神の左手悪魔の右手(kami no hidarite akuma no migite).
This is Japanese horror manga by 楳図かずお(umezu kazuo)