Maburaho
Tags: flashback

Plot synopsis:
Maburaho is set in a world where every character has the ability to use magic, however everyone's magic is not equal. Each person in the story has a different degree of magic and a set number of times that they can use their magic. The average person is able to use magic fewer than a hundred times, however some people are able to use magic several thousand times. Because of this, a person's social standing is determined by the number of times that he or she can perform magic. If someone uses up all of their magic, his or her body turns to ash and is scattered into the winds.
The series first introduces us to Kazuki Shikimori, a second year student from an elite magic school, Aoi Academy. However, unlike his classmates, Kazuki can only use his magic eight times before he turns to dust. As a result, he is at the bottom of the school's social pecking order. However things change one day when Yuna Miyama shows up in his dorm room and declares that she is his wife. Moments later, Kuriko Kazetsubaki and Rin Kamishiro appear at Kazuki's dorm, the former in order to obtain his genes and the latter to kill him to escape her obligation to marry him. Kazuki learns that he is a descendant of most of the world's greatest magicians from both the eastern and western worlds. Even though he has a feeble spell count, his offspring has the potential of becoming a powerful magician.
Despite his weak spell count, each spell he performs is treated as an epic event. Kazuki's magic is referred to as the most powerful magic in the world able to achieve miracles. Due to Kazuki's kindness, his spell count begins to drop as he uses his magic on behalf of each girl. First by making it snow in the middle of summer to cheer up Yuna. Second by pulling Yuna out of a vortex that also merges the boy's and girl's dorms together. Kazuki uses his magic again to destroy two Behemoths in order to save Kuriko, who was unable to defeat them. And then, Kazuki reverses time to save Rin's homemade box lunch. He also uses it to save his childhood friend Chihaya Yamase after a monster summoned by Kazuki's classmates appeared at the school festival. Not long after, Yuna accidentally releases an incurable retrovirus on herself which also creates a doppelganger of her with the opposite of all her qualities (ex. the real Yuna loves Kazuki, the clone wants to kill him). Kazuki uses his sixth spell to obliterate the clone. Finally, Kazuki uses his last two charges in order to save Yuna's life from the virus.
Each event leaves an impression on the girls and they attempt to keep Kazuki from using any more of his magic and eventually search for ways to increase his spell count. However, their attempts fail when halfway through the series Kazuki uses the last of his magic to save Yuna from the magical retrovirus. However, while Kazuki turned to ash and the ashes scattered, his ghost remains.
At this point in the story, Shino Akai appears in order to capture Kazuki and add him to her ghost collection. The girls try to protect Kazuki from Shino and eventually learn that Kazuki's ashes had been scattered into each of their own hearts. But before Kazuki's ashes were completely returned to him, Shino informs Rin and later the rest of the girls that this is not the first time someone's ashes have been scattered and later restored. However, when Kazuki's ashes are returned to him and his body restored, he will lose all of his memories. Knowing this, the girls still return Kazuki's ashes to him. At the very end of the anime series, it is shown that instead of losing his memories as a side effect of restoring his body, Kazuki has now split into ten different bodies.
In the novel, the side effect of Kazuki's restoration was gaining a special magical body that can cause disaster to the whole world if he lets out his magic powers. Another side effect of Kazuki's restoration is the overflowing of his magical powers every now and then causing minor mishaps and sometimes great chaos.