The Irregular of the Royal Academy of Magic is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

A Manga adaptation of the Light Novel "The Irregular of the Royal Academy of Magic", serialized in Weekly Young Jump.
"Magic." A sacred mystery usable only by those chosen. One day, a child from the slums named Ars finds he has the power to use magic. A sorcerer by the name of Genos Wilzard learns of his talent and raises him, turning him into the greatest of assassins. One day, Genos gives him an order: To enroll at the Magic Academy...!?