Ayumu Aikawa is a 16-year-old high school student who is tragically murdered while investigating a suspicious house. However, he soon awakens next to a strange armored girl called Eucliwood Hellscythe. She reveals herself to be a necromancer who has revived Ayumu, consequently turning him into a zombie! Now immortal, Ayumu sets out to hunt down his killer. One day, while searching in a cemetery, he encounters a boisterous young girl named Haruna, who is fighting a bear with a chainsaw while dressed as a magical girl. After she kills the beast, Haruna attempts to erase Ayumu's memories of her, but he instead absorbs her magic for himself. Stripped of her powers, Haruna now orders Ayumu to take up her role of hunting strange creatures known as Megalo, monsters that roam the human world and terrorize the population. Kore wa Zombie Desu ka? follows the daily antics of the human-turned-zombie Ayumu as he begins his new, ludicrous life where the supernatural becomes the norm.

Several months have passed since the infamous Ginza Incident, with tensions between the Empire and JSDF escalating in the vast and mysterious Special Region over peace negotiations. The greed and curiosity of the global powers have also begun to grow, as reports about the technological limitations of the magical realm's archaic civilizations come to light. Meanwhile, Lieutenant Youji Itami and his merry band of female admirers struggle to navigate the complex political intrigue that plagues the Empire's court. Despite her best efforts, Princess Piña Co Lada faces difficulties attempting to convince her father that the JSDF has no intention of conquering their kingdom. Pressured from both sides of the Gate, Itami must consider even more drastic measures to fulfill his mission.

When Keyaru acquired his powers as a Hero who specialized in healing all injuries regardless of severity, it seemed that he would walk the path to a great future. But what awaited him instead was great agony; he was subjected to years of seemingly endless hellish torture and abuse. Keyaru's healing skills allowed him to secretly collect the memories and abilities of those he treated, gradually making him stronger than anyone else. But by the time he reached his full potential, it was far too late—he had already lost everything. Determined to put his life back on track, Keyaru decided to unleash a powerful healing spell that rewound the entire world back to the time before he began to suffer his horrible fate. Equipped with the anguish of his past, he vows to redo everything in order to fulfill a new purpose—to exact revenge upon those who have wronged him.

To the outside world, Hanabi Yasuraoka and Mugi Awaya are the perfect couple. But in reality, they just share the same secret pain: they are both in love with other people they cannot be with. Hanabi has loved her childhood friend and neighbor Narumi Kanai for as long as she can remember, so she is elated to discover that he is her new homeroom teacher. However, Narumi is soon noticed by the music teacher, Akane Minagawa, and a relationship begins to blossom between them, much to Hanabi's dismay. Mugi was tutored by Akane in middle school, and has been in love with her since then. Through a chance meeting in the hallway, he encounters Hanabi. As these two lonely souls spend more time together, they decide to use each other as a substitute for the one they truly love, sharing physical intimacy with one another in order to stave off their loneliness.