Its the prologue of Jujutsu Kaisen.
The series is about 23-year-old Canadian Scott Pilgrim, a slacker and part-time musician who lives in Toronto and plays bass guitar in the band Sex Bob-omb. He falls in love with American delivery girl Ramona Flowers, but must defeat her seven evil exes in order to date her.
The deadline is his 18th birthday... Let's search out all the reborn demons that are still hidden in the academy! After transferring to such a huge school, Aitan Gakuen--Yuki, who possesses a disaster attraction physique--has been told that he is actually the reincarnation of Momotaro from folklore. If he doesn't break the curse cast upon him by the demons he defeated in his previous life, he will die upon reaching the age of 18...!
Hikaru, Umi, and Fuu, girls from separate schools, find themselves linked together as they fall through the floor during a field trip to the Tokyo Tower. They land in a place called Cephiro, where their will controls what happens. They meet with Guru Clef and find out that they were summoned to save Princess Emeraude who has been imprisoned by High Priest Zagato. They learn magic and acquire weapons on their quest to save Cephiro from the evils of Zagato.(Source: ANN)
From MangaHelpers: In a strange twist on Arthurian legend, young Art pulls the magical sword Excalibur out of a stone--only to find himself as one of a million Arthurs, fighting to defend the island of Britain from enemies and to earn the rank of the true king. Art is pretty puny, but his childhood friend Ligu (who was also chosen by an Excalibur) tries to keep him from being immediately killed. Soon Art lives in a castle with knights, which are created beings who serve the kings. From the respect with which he treats the knights, he inspires some to hope he becomes the true king. But is that really achievable by a scrawny crybaby like him? [tethysdust]
Ayumi and Chika are always together, but as they grow up, time drifts them apart. Only when that happens does a realisation strike someone.
A redrawn variant of Chapter 1: Tragedy.
Wait! My heart's beating? Is it because of him!?
From Tokyopop: Sasshi's world is in disarray. His best gal pal, Arumi, is about to move away, and his Osaka neighborhood is being demolished in the name of urban renewal. However, this little neighborhood has some surprises under its concrete -- it's actually a portal to parallel universes. And when this section of the city is leveled, the portal is cracked wide open. Sasshi and Arumi soon find themselves being hurtled from one strange world to the next! Making matters even more surreal, is the fact that these worlds seem to spoof and mock popular movies, video games, manga and anime!
The world is full of suffering. Times are good for Alakshmi, the Goddess of Bad Luck. Too good in fact, as it's making her gain weight at an alarming pace. Now she must go to the human world and do good deeds to slim down.
"Year 252 M.C, in this era which plants are almost extinct and the land is barren, a strange disease developed. 'Shinigami's flower,' the unique lethal flower that carries death." The disease is curable if found in the early stages but if left till transformation stage it becomes lethal and the only option left is extermination. These are all dealt with by request to 'Gokurakuen,' the national medical institution specializing in dealing with shinigami's flowers. Our protagonist, Doctor Ichinose Souma, is the class representative of Mobile Team Unit Class 1. As his class gets too few requests, he and his assistant Hina often get into trouble interfering with other class's jobs.