Kaito's mother, who died before the events of the anime.   ~!She's not his real mother, but a giver of the POG. That was assigned to observe Kaito's progress in solving puzzles. She loved Kaito as her own son, therefore she disobeyed the POG's orders and saved Kaito's life.!~

Kaito Daimon would be a completely average high school student except for one thing: he's a 'demon' at solving puzzles. Kaito is so brilliant, in fact, that when he's asked to take some 'special' tests of his unique ability, he immediately suspects that the test itself is a test. Kaito suddenly finds himself caught up in a lethal Philosopher's Puzzle made by the sinister group POG, a murderous maze of trap upon trap, where failing to solve the secret correctly will result in death! Fortunately, Kaito's skills prove up to the first test, both for himself and his childhood friend Nanoha, who is also caught up in the deadly scheme. But now that he has been designated as a Solver, he is pulled into a new life where he must travel the world with other Solvers, attempting to solve the latest deadly riddles left by POG. There's a new conundrum around every corner and each deception could lead to death, but once a riddle has been posed, you can count on Kaito to unfold, unravel and unlock it!<br><br>
(Source: Sentai Filmworks)

"Are puzzles really necessary in this world?"

In order to restore Jin's memory, Kaito and his friends go on a puzzle-viewing journey to England. As they're walking through the underground maze beneath the church, where young Kaito and Rook first met Jin, a mysterious girl appears in front of them.

Jin calls the girl by the name "Raetsel". It seems they know each other. However, she suddenly disappears and takes Jin with her. What's more, the traps in the underground maze are activated and start coming after Kaito and his friends.

(Source: www9.nhk.or.jp)

Shizuka Daimon