into the sheath

**Whistle related settings** (part of the narrative is excerpted from the Internet, and part of it is from the author's random fabrication):

**sentinel**:

The five senses are extremely sharp, the combat power is much higher than that of ordinary people, and the personality is usually biased toward wildness.

**Guide**:

Possess strong spiritual power, strong empathy, and can perceive other people's emotions.A guide with strong empathy can even influence the thinking of others, attacking and seeing through the enemy on a spiritual level.

**Ordinary people**:

Ordinary humans without any supernatural powers.

**Rampage**:

A condition in which Sentinels become deranged after being overstimulated, often accompanied by symptoms such as body pain, irritability, aggressiveness and bloodthirsty, and eventually complete loss of sanity.

The time required for complete onset of the disease varies from person to person.

**Quantum Beast**:

It is also called "spiritual body" in some places, and it has a "symbiotic relationship" with the sentinel guides. It should be some kind of creature that exists outside the three-dimensional world.Their image can be any animal, but generally speaking, the quantum beasts of the guide are mostly small animals, or herbivorous animals with a gentle personality (with very few exceptions); .

Theoretically, the Quantum Beast can attack the sentinel guide, but ordinary people cannot see or perceive it, and it will not have any effect on ordinary people.

**Locked House**:

The place where Berserk Sentinels are held and processed.

**Bonding & Spiritual Connection**:

Spiritual connection is divided into temporary connection and permanent connection.

Generally speaking, temporary connections will appear between sentinel guides who are temporary partners. There are various means to establish connections, but this form of connection is not very stable.

The permanent connection (also called a bond) is relatively more formal and more stable. It belongs to a bonded relationship between the sentinel guides and requires a combination of body and spirit to be finalized.

**Pseudo-guide pheromone**:

An artificial preparation used to appease unbound Sentinels.

A certain dose of pseudo-guide pheromone can soothe the Sentinels, but too high a concentration can be counterproductive.

**Sanctuary**:

An institution responsible for educating newly differentiated sentries and guides, where sentinel guides will learn how to control their own abilities, how to build and maintain information barriers, etc.With the passage of time, most of the sanctuary are now guides. Even if there are a small number of sentries studying in it, they will choose to leave after learning the basic construction and maintenance of information barriers.

**Dark Sentinel**:

The most powerful type of sentinel, the probability of appearing is extremely low, has extreme self-control ability, can control one's emotions well, theoretically there is no need for the assistance of a guide when emotions are out of control.They are born leaders, and at most there will only be one at a time.

The reason for the formation of the Dark Sentinels is still unclear, but they are natural leaders, and there will only be one at most at the same time, who can influence other Sentinels or send signals to the group.

**Other Settings**:

Nothing.

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3/25 - Added explanation for Dark Sentinel