Is Demon Killer Springs Based On A Manga Or Anime?

A 25 years old boy named John is suddenly shot by his friend, which results in his death, but is reincarnated again as the new Demon King. Unfortunately, he agains dies in a battle. This time also he is reincarnated but as a human. Follow Vis' adventure as he gets revenge, becomes a demon and makes his own harem.

Serra is a normal senior high school student who works really hard every night and weekend to pay off her parents' debts from loan sharks. But when she couldn't keep up with payments anymore, she decided to end her life. Surprisingly, she woke up in a different light-- in another world. What's more shocking was when she is addressed by one of the people as the demon king's bride.

A normal girl just as usual working every day. This changed when she met a demon. She made a contract with the demon to help her. She just want to use her demon, but she find that she can't help fall in love with the Demon

300 years ago, humankind created their own nightmare. Demons, are originally humans but the lust for power changed them inadequately, this is humans own doing. Around 300 years ago, a large asteroid bombarded the earth's very ground. This is the beginning of the birth of demons. This meteor was large, but out of the blue, a mysterious lifeform is intact in it's very core. A human named Cruzius Akiyoma was intrigued when witnessing these menacing looking creature. He interpret this as a blessing from heaven. He then owned the creature and conducted an experiment. He was surprised when he saw the structure and building blocks of life of this creature. He obsessedly pictured this as a one stepping stone through human evolution. He extracted the DNA of the creature and modified it in able to merged it to human DNA. Without any hesitation he then merged his DNA to the DNA of the creature. He is willing to offer his body to attain his goal, thus sacrificing his body is necessary. After the merging, he was surprised because nothing in particular happened. But, he suddenly felt a surging power circulating through his body. He screamed in pain as his body is gradually changing. Darkness fell upon humans as the scream of the first demon engulfed the sky, seas, forest, and fortress.

Miaka Von Speltsper, the myth, the legend and the daughter of two Gods. Miaka, the Demon King and the head of the Dark Council is the most powerful demon ever known to mankind, but she has a secret. She’s a hybrid. And the world she lives in has hunted down and eliminated every single hybrid in all the dimensions. But now…someone knows her secret, someone who has the power to destroy her. However, the world is changing and one of those changes is Kaleb Takeshi, the man with extraordinary eyes who has stolen Miaka’s heart with just one glance. But there is something about Kaleb that Miaka can sense but can’t describe. And not only is he human, he’s an enemy who has decided to give his loyalty to her. In this world of lies, deceit and betrayal; can Miaka trust her heart or will she have to choose century’s old traditions to stay alive? Because if she dies, it will truly be the end of the world.

Amanda has been living happily in the village for years. Her ancestor, a Mage that helped the Hero in subjugating the Demon King about 500 years ago, made sure that the village becomes rich and abundant. Along with her friends – Irene, Jessica, and Grace – they promised to spend the next harvest festival together as they did this year. Until Jessica suddenly left with her lover. Amanda found it mysterious. After a year, Amanda was introduced to a noble during the Harvest Festival. It was supposed to be a routine marriage interview until she woke up in a place that she did not recognize. In the mountain beyond the thick forest that surrounds the village, a large castle looms with darkness. Will Amanda find the truth about her situation, or will she find love instead?