Kinsou no Vermeil: Gakeppuchi Majutsushi wa Saikyou no Yakusai to Mahou Sekai wo Tsukisusumu

A student at the magic school, Alto, who was on the verge of repeating the school year, accidentally found a book that activated a magic circle, and as a result, summoned the sealed devil Vermeil! Vermeil is a very unhealthy older sister with a power devastating enough to be called a disaster! The apprentice magician walks side by side with the strongest being in existence!!