Satosuka

Canon
During a Thunderstorm,At Kisaragi Academy Satoshi and his Classmates were listening to Ghost stories from their Class Rep Ayumi Shinozaki.The Thunderstorm knocked out the power,Satoshi walks to the door with a candle checking to see who was at the door it was revealed to be Ms Yui(his Teacher) along with his Little girl holding an umbrella by the name of Yuka Mochida(Satoshi's sister).Yuka brought the umbrella to Satoshi since it was raining badly as well as introducing herself to the class much to Satoshi's classmates excitement.After it was revealed Satoshi's female Classmate Mayu is transferring to a new school,Ayumi wanted to do Sachiko Ever after Charm with a paper doll she found on the Internet which was said to bond their Friendship forever.However it Caused An Earthquake and Everyone was sent into Heavenly Host(An alternate Dimension aka the Land of the dead).