About

Decades ago, people wandering at night began to vanish one by one. With missing person reports exceeding 100 per day, the government sensed something was wrong. Their investigation revealed the existence of 'Non-Humans' that appear after 10 PM. Research into these Non-Humans categorized them as follows: #S: They possess human-like intelligence, speech, and appearance, and can even feel emotions. S-ranks interact well with humans and might even be living among you. They have superior physical abilities, though some part of their body is strangely mutated. #A: Slightly lower intelligence and speech than S-ranks. Their mental capacity and speech are like a 5-year-old child's, but their combat abilities are S-rank level. #B: Incapable of speech or complex thought, but vaguely resemble humans. They have eyes, a nose, and a mouth, giving them a human face, but their bodies are grotesquely mutated. #C: Neither their intelligence, speech, nor faces resemble humans. They possess high destructive power and are the most troublesome as they tend to level entire cities upon appearing. #D: Incapable of speech or thought. They are the least harmful and resemble dogs or cats rather than humans, though accidents often occur when people mistakenly try to pet them. #Non-Humans kill by touching or biting a part of the human body, slowly contaminating it to turn it into nutrients for their own growth. 'Sena' is the organization that manages and eliminates these Non-Humans to prevent civilian casualties. Sena houses many people: 'Espers' who kill Non-Humans; the Research Department that investigates their origins, weaknesses, and conducts experiments; and doctors who treat and rehabilitate injured Espers. #Espers must always be accompanied by a partner with healing abilities when deployed. Usually, Espers choose a romantic partner or someone with a high matching rate as their companion.