17 years ago, immortals first appeared on the battlefields of Africa. Later, rare, unknown new immortal lifeforms began appearing among humans, and they became known as Ajin (demi-humans). Just before summer vacation, a Japanese high school student is instantly killed in a traffic accident on his way home from school. However, he is revived, and a price is placed on his head. Thus begins a boy's life on the run from all of humankind. Written by animenewsnetwork.com

They are called Chiropterans, ravenous creatures that can change their form, disguising themselves as human beings. Immortal creatures that feed off blood, they hide themselves among us. An organization called the Red Shield has been waging a private war to wipe them out. Now the struggle has grown. Saya Otonashi is a normal high school student who suffers from amnesia; she can't remember anything before the past year of her life. Then one day, a man named Hagi appears and gives her a katana, and her destiny is only partially revealed. The journey for the truth begins... Written by songmaster2005