時使い魔術師の転生無双～魔術学院の劣等生、実は最強の時間系魔術師でした～

Arvis is a poor, low-achieving student at a remote magic school. One day, he was given the impossible task of defeating the smartest student in his school, or else he will be expelled. Arvis looks after his little sister who's blind and frail, and depends on the scholarship from the school to survive, so he started training as hard as he could! Not only did he not acomplish anything, he passed out from pushing himself too far. But then, he had a mysterious dream. In the dream, he was a legendary mage in his previous life, and was using the now extinct time magic to make quick work of demons! When Arvis woke up from the dream, he had the ability to use the legendary time magic?! (Source: Manga UP!)