Return of the Alchemist (錬金術師の帰還 Renkinjutsu shi no kikan) is the sixth novel of the Strike the Blood series.
When all the students depart for a school field trip to the mainland, Kojou is delighted to hear that he'll finally get a chance to be free of observation for at least a little while, whereas Yukina has mixed feelings about the whole situation. But events move quickly when an alchemist by the name of Kou Amatsuka appears, with the goal of reviving the holy grail of alchemy—a liquid-metal life-form known as "Wiseman's Blood." As the crisis deepens, even Asagi becomes involved when this alchemist's relic grows more and more uncontrollable. What can the world's strongest vampire do?!
- Chapter One: The Watchdog's Holiday
- Chapter Two: The Premature Bereavement
- Chapter Three: Return of the Alchemist
- Chapter Four: The Sacrificial Victims
- Chapter Five: The Undine
The volume was adapted into episodes 20-22 of the anime.