Tasogare

During the Second World War, the protagonist was a clone subject to experimental injections that granted accelerated healing, enhanced senses, and functional immortality. The clone was then placed in long-term hibernation alongside three others — including one who was once a friend. The protagonist's sleep is abruptly interrupted when that former friend attempts to kill them. The fight might have gone either way, but two girls enter the domain and distract the attacker long enough for the protagonist to be dragged to safety. After a few words in the hospital, the protagonist is discharged and taken home by one of the girls — where they discover they have been dormant for more than 50 years.