Nightwatchers

The Nightwatchers are one of the Three Great Guardian Clans, along with the Untitled Sages and Gravekeepers. They were reputed to be the strongest Guardian clan before the invention of lightbulbs severely weakened their power, causing them to forfeit that title to the Gravekeepers.

Background
Before the invention of artificial lighting, humans feared the darkness and chose to shut themselves within their houses when night falls and escape from reality through sleeping. When night falls, monsters roam the world freely. The Nightwatchers, who were the only humans that remained active during the night, were responsible for keeping these monsters under control under the ruse of "watching the night". Being capable of monitoring all the monsters within thousands of miles, the Nightwatchers were crowned as "Night Conquerors" due to their immense power and dominance over monsters and demons alike.

At some point in time, the Nightwatcher clan separated into multiple families and scattered across China, with the members who had the purest heritages splitting into two main branch families and residing in the North and the South. The other families who did not possess bloodlines as pure as the main branch families were labelled side branch families and deemed inferior. According to Bao Huajuan, this prejudice once caused conflicts between the main branch and side branch families that almost wiped out the side branch families entirely. As a result, main branch Nightwatchers act modest and humble when interacting with side branch Nightwatchers to avoid being mistaken for being discriminatory.

Before the invention of lightbulbs, the Nightwatchers considered themselves the strongest guardians, as a result they were egotistical and couldn't care less about the other two Guardian clans. After the invention of lightbulbs, the Nightwatchers were significantly weakened since there was no more absolute darkness after the widespread usage of artificial lighting, and resulted in them forfeiting the title of "the strongest Guardian clan" to the Gravekeepers.

Thirty years ago, a certain Nightwatcher defected from the Nightwatcher clan, leading to them being labelled as a traitor. They possessed the Darkening ability.

Structure
The Nightwatcher clan is composed of two main branch families (宗支, Zōng Zhī): the Northern Family (北方家族, Běi Fāng Jiā Zú) and the Southern Family (南方家族, Nán Fāng Jiā Zú), and numerous side branch families (分支 Fēn Zhī). The main branch families are responsible for selecting and sending the strongest Nightwatcher from one of the two families to the Department of Night as a representative of the clan, while the side branch families may have their Nightwatchers recruited to governmental agencies, such as police departments to take care of sudden supernatural incidents that the Department of Night is unavailable for.

Traditions
The two main branch families concurrently host an annual Demon Flag Awakening Test (煌妖幡的觉醒测试, Huáng Yāo Fān De Jué Xǐng Cè Shì) that examines the new generation of Nightwatchers' potential. During the test, participants, who are generally eight to ten years old (the optimal age for Nightwatchers to awaken the power to control Demon Flags) take a normally forbidden steroid that will awaken their latent powers and allow them to control the maximum amount of Demon Flags possible for them. However, the steroid is stated to dangerous for those who are physically weak, and even might cause the consumer to become physically disabled. Those who fail to control a Demon Flag during the test are allowed to participate again until they reach the age of ten. If they still fail to meet the one Flag requirement, they will permanently lose their chance to become a Nightwatcher and will end up as a lackey in the family. Master Lan stated that only those who possess a pure enough bloodline can control Demon Flags, though the amount can increase through painstaking training. He also stated that one Flag is enough to meet the requirement of a Nightwatcher, and those who can control more than three Demon Flags are considered "doted by the heavens" since it is extremely difficult to control more Demon Flags afterwards.

Ancestral edicts (祖训, Zǔ Xùn) are considered the supreme laws of the Nightwatcher clan. They dictate the training methods for Nightwatchers, the representative selection process, as well as the countermeasures for Darkened Nightwatchers. The following are the specified edicts mentioned throughout the series:
 * When selecting the Nightwatcher who will represent the clan and join the Department of Night, the Nightwatcher who can wield the most Demon Flags between the Northern and Southern families' candidates chosen from the Demon Flag Awakening Test is selected as the representative.
 * Nightwatchers are encouraged to have an enjoyable hobby that can kill time, such as the arts or any other entertainment method. As long as the hobby is not immoral or illegal, elders are advised against intervening even if it can be considered indecent. This edict is enforced due to the fact that Nightwatchers are prone to developing depression among other mental illnesses since they are subjected to extreme loneliness while patrolling the night, and thus would need a hobby as spiritual sustenance to prevent them from succumbing to isolation and taking their own lives.
 * A Nightwatcher trainee must complete a total of two years worth of training with another trainee as partners in order to qualify as a standard Nightwatcher and patrol the night alone. Either trainee are allowed to switch partners if they can not tolerate the other's behavior.
 * Every Nightwatcher in the family is responsible for completely subduing a Darkened Nightwatcher while their powers are suppressed. The utmost priority is to impair the darkened one's mobility, since once they regain their powers and are still mobile, they could overpower everyone and cause the loss of more innocent lives. If one were to accidentally kill the darkened one while attempting to subdue them, they are not held accountable for the death after the incident is resolved.
 * If a Darkened Nightwatcher were to go berserk while being treated, if they are alive after being subdued, the lowest punishment they receive is the crippling their powers.

According to Sui Fenger, cousins in the two main branch families were allowed to marry each other, usually with the marriage overseen by elders. This tradition was abandoned after incest was made illegal.

Morals
Nightwatchers are widely feared by monsters for their ability to enslave them for eternity using Demon Flags, as Flag Demons are forced to serve under their master and are no longer able to reincarnate if they die. Nightwatchers are fairly lenient, as they prefer to capture monsters if they didn't committed any crimes involving deaths of humans, and are even supportive of peaceful relationships between humans and monsters. But if a monster were to commit murder, Nightwatchers will not hesitate to execute them.

According to Ye Yan, Nightwatchers are not allowed to order Flag Demons to attack ordinary humans, as it is against the rules within the clan.

The most derogatory term to call a Nightwatcher is a "Gong Player" (敲锣的), as seen when Ye Yan became extremely angry and called Huang Xiaoyan a "Half Sage" (半仙), an equally derogative term for Untitled Sages, when she called him that.

Abilities

 * Summoning Beast (召唤兽 Zhào Huàn Shòu, lit. "Summon Monster"): A few Nightwatchers throughout history have searched for and formed contracts with creatures to serve as their summoning beast. Once the contract is formed, the Nightwatcher can summon the creature by saying their name or shouting "Summon" (召唤). Once summoned, the summoning beast's existence is maintained by expending the summoner's stamina. If it were to sustain damage or exert its power, the depletion will be intensified. Once the user's stamina is completely depleted, the summoning beast will disappear. If the user wishes to continue maintaining the summoning beast even after they have no more stamina, they must sacrifice their vitality in exchange.


 * Spirit Shock (元气震 Yuán Qì Zhèn, lit. "Spirit Tremor"): After accumulating enough negative emotions from experiencing grievances, a Nightwatcher can release the stored energy into their vicinity, indiscriminately knocking creatures around them unconscious before falling unconscious themselves shortly afterwards, though they will usually wake up before the others due to a temporary boost in resistance. While using this technique and before fainting, the Nightwatcher's eyes will glow. The time a person is rendered unconscious depends on the degree of their strength in comparison to the user's and their stamina: people established to be powerful and strong-willed fall unconscious for considerably less time than the weak-willed, but may faint for longer if they were exhausted beforehand. This technique cannot affect organisms that were unconscious before it was used, on organisms that were alertly focused on the user, or Flag Demons that are inside Demon Flags.


 * Timed Knockout (定时锤 Dìng Shí Chuí, lit. "Timing Hammer"): By controlling their strength and striking a person's head with a blunt object, a Nightwatcher can knock them unconscious for a certain duration. The time of unconsciousness induced in one hit can range from five seconds to an hour, but consecutive hits can extend the duration. This technique cannot affect organisms who are alertly focused on the user and can be undone if the unconscious creature takes any damage other than a Timed Knockout attack.


 * Time Guessing Pinch (掐心算点 Qiā Xīn Suàn Diǎn, lit. "Heart Pinch Calculate Time"): By pinching their fingers, a Nightwatcher can accurately calculate the time of day down to seconds, even if the environment around them has not changed. The time is usually denoted with the traditional Chinese time standard.


 * Animal Mimicry (仿生口技 Fǎng Shēng Kǒu Jì, lit. "Creature Mimicking Ventriloquism"): A basic technique learned by Nightwatchers. They can deceive and distract people by mimicking the sound of an animal.


 * Air Shock (空气震 Kōng Qì Zhèn, lit. "Air Tremor"): A Nightwatcher technique that allows the user to burst off their clothes through an air shockwave. While using this technique, the Nightwatcher's eyes will glow similarly to Spirit Shock. This technique can also be used on others by transferring it to them through touch, causing the receiver's clothes to burst off shortly afterwards.


 * Muscle Contracting Hemostasis (止血收肌法 Zhǐ Xiě Shōu Jī Fǎ, lit. "Blood Stopping Muscle Contraction Method"): By contracting their muscles around a laceration wound on their body, a Nightwatcher can stop the bleeding from that wound.


 * Night Vision (夜视术 Yè Shì Shù, lit. "Night Vision Technique"): A technique used by Nightwatchers that allows them to see in the dark.


 * Penta-Shockwave (五方烈震 Wǔ Fāng Liè Zhèn, lit. "Five Corner Violent Quake"): By slamming the Soul Mallet onto the ground, a Nightwatcher can create a shockwave strong enough to send debris flying everywhere. This move is used to create an opening for attacks or kick up debris to obscure one's position.


 * Darkening (黑化 Hēi Huà, lit. "Blackening"): A form achievable by a Nightwatcher who has invoked their dark personality(黑暗人格, Hēi Àn Rén Gé), born from their negative emotions. By succumbing to their inner darkness and forfeiting their body's control to the dark personality, a Nightwatcher can assume this special state, which is indicated physically with the blackening of their sclerae. A Darkened Nightwatcher exhibits complete apathy to everything around them and focuses only on killing other creatures. While Darkened, aside from a significant boost in strength and speed, a Nightwatcher also gains the ability to see and physically interact with souls, release concussive shockwaves from themselves, and generate destructive green energy from their hands that can be discharged as explosive beams. However, extreme emotional outbursts from their normal personality, such as embarrassment could force a Nightwatcher out of this form, indicated by their eyes returning to normal one after another. By learning to accept and live with their inner darkness instead of resisting it allows a Nightwatcher to attain the ability to transform into a Night Conqueror.


 * Night Conqueror (黑夜主宰 Hēi Àn Zhǔ Zǎi, lit. "Dark Night Overlord"): The ultimate form only achievable by a Nightwatcher after conquering their inner darkness. After transforming into a Night Conqueror, a Nightwatcher's power is vastly increased. By throwing their Soul Mallets, they can create tremendous explosions at the points of impact, and completely obliterate a monster's body and soul with a direct hit. They can perform the Timed Knockout attack without the aid of objects, such as through a stomp. Additionally, the Nightwatcher can intuitively locate and sense the presence of anything within 5 Chinese miles, even if their five senses are hampered. The abilities of their Darkening form are also accessible, such as channeling green energy. The power of a Nightwatcher while in this mode largely depends on the power of their bloodline, which is directly proportional to the number of Demon Flags they can wield. Due to the disruption of natural energy brought about by artificial lighting, the Night Conqueror transformation is incredibly unstable in modern times, requiring true darkness as a catalyst for the transformation. Even if transformed, the form is short-lived, and the Nightwatcher will lose consciousness afterwards as well as have no recollection of their actions while transformed.


 * Darkness Creation: While as a Night Conqueror, a Nightwatcher with a bloodline powerful enough to presumably control more than five Demon Flags can project darkness over an incredibly large area. While in this darkness, unless a creature has the ability to see in the dark, their vision is completely obscured. The Nightwatcher may choose to let themselves be seen.


 * True Spirit Clothing (真气化衣 Zhēn Qì Huà Yī, lit. "True Qi Clothing Conversion"): When a Nightwatcher assumes the Night Conqueror form, they don a black hooded robe with red borders around the edges either by reconstructing their clothing or manifesting it through energy. This transformation is automatic, and usually acts as an indicator of their transformation.
 * Intimidating Pressure: While as a Night Conqueror, a Nightwatcher possesses a dominating aura that can induce fear or even paralyze creatures nearby. While stronger creatures can resist the effects, they may still shiver in fear and have difficulty breathing when facing a Night Conqueror. This pressure can be amplified, affecting creatures in a wider range upwards 600 meters.


 * Temporary Demon Flag Creation: A Nightwatcher can create temporary Demon Flags using any fabric stained with monster blood and their own. In contrast to the standard Demon Flags that can store Flag Demons for eternity, depending on the amount of blood used, the Flag Demons stored in the temporary Demon Flags can live for a certain amount of time before dying. Otherwise, these Demon Flags have the same properties as actual Demon Flags and can be telekinetically controlled by their Nightwatcher.


 * Self-Atomization (雾化自身 Wù Huà Zì Shēn, lit. "Atomize Oneself"): A Nightwatcher can instantly transform their physical bodies into green fog, similar to Flag Demons, and vice versa. While in their Flag Demon form, the Nightwatcher is immune to attacks that can only affect their physical bodies since they are gaseous. A Flag Demon must be sacrificed for the Nightwatcher to transform once, and additional sacrifices are needed every once in a while to maintain the transformation.


 * Flag Demon Regeneration (旗妖大补血 Qí Yāo Dà Bǔ Xuè, lit. "Flag Demon Invigorate"): While transformed into a Flag Demon, if the Nightwatcher were to sustain non-lethal injuries, they can regenerate their bodies by sacrificing a Flag Demon.


 * Night Purge (黑夜清君侧 Hēi Yè Qīng Jūn Cè, lit. "Dark Night Removing the Evil Ministers Around the Emperor"): An execution technique used by Nightwatchers in case their Flag Demons revolt against them. By releasing a green aura from themselves, the Nightwatcher indiscriminately kills all Flag Demons and any gaseous life form around them instantly. As such, this is a forbidden technique and is only used when no other options are left.


 * Flag Demon Self-Destruction (旗妖自爆 Qí Yāo Zì Bào, lit. "Flag Demon Self-Explode"): A Nightwatcher can order their Flag Demons to self-destruct. When doing so, the Flag Demons swell up, then rupture and explode violently into a cloud of green smoke, damaging creatures nearby while destroying themselves. This explosion cannot affect other Flag Demons, or a Nightwatcher transformed into their Flag Demon form. The damage dealt persists over time and even affects the injured person's soul.


 * Flag Demon Missile (旗妖爆弹 Qí Yāo Bào Dàn, lit. "Flag Demon Bomb"): A Nightwatcher orders a Flag Demon to fly towards an enemy and self-destruct near them.


 * Flag Demon Revival: If a Flag Demon were to be destroyed, a Nightwatcher can sacrifice another Flag Demon to resurrect it.

Equipment

 * Soul Gong (镇魂锣 Zhèn Hún Luó, lit. "Soul-Reposing Gong"): A main branch Nightwatcher exclusive weapon. If struck by the Soul Mallet, it can produce a sound that either renders anyone within close proximity to the gong unconscious or temporarily immobilizes anyone who heard the sound other than Nightwatchers, who have certain levels of immunity to losing consciousness and paralysis. However, if repeatedly struck within a short timeframe, the immunity will start to weaken and eventually the Nightwatcher themselves will be affected by the sound, showing signs such as extreme fatigue and nose bleeding. Even if they are shattered, Soul Gongs can still produce the immobilizing sound if the pieces are taped back together and can be welded back together through unknown methods. The immobilizing effect only works on the receivers' bodies, therefore it can not stop someone from mentally controlling or summoning a weapon.


 * Soul Mallet (镇魂锤 Zhèn Hún Chuí, lit. "Soul-Reposing Hammer"): A main branch Nightwatcher exclusive weapon, it can be used to strike the Soul Gong to create an immobilizing sound or physical attacks. When a Nightwatcher assumes the Night Conqueror form, the Soul Mallet's power increases drastically, becoming capable of producing large explosions upon impact when thrown and destroying a monster's soul along with its body in one direct hit.


 * Demon Flag (煌妖幡 Huáng Yāo Fān, lit. "Brilliant Demon Banner"): A Nightwatcher exclusive equipment. It is used to capture monster by atomizing their bodies into green fog along with their soul and enslave them as Flag Demons for eternity, courtesy of the numerous formulae programmed into them. Flag Demons are capable of making themselves invisible and intangible by turning themselves into green smoke, or solidify themselves to physically attack. Nightwatchers are also able to telepathically communicate with their Flag Demons within a few hundred meters. Nightwatchers are also capable of telekinetically moving Demon Flags within a few dozen meters of themselves, which allows them to hide their flags around the battlefield for sneak attacks with their Flag Demons. Main branch Nightwatchers possess purer bloodlines and are thus usually able to control multiple Demon Flags. According to Wang Shengli, a Nightwatcher that can control more than four flags is able to store three Flag Demons at most in one flag. However, this is a false claim intentionally spread and perpetuated by the Nightwatchers. In reality, the number of Flag Demons a Nightwatcher can have exponentially increases depending on the number of Demon Flags they control, being equal to 2 to the power of number of Demon Flags minus 1. For example, a four-Flag Nightwatcher can have 8 Flag Demons, a five-Flag can have 16, etc..

Members
Ye Yan: The current representative guardian of the Nightwatcher clan and the main branch families. Born in the Northern main branch family. Wields eight Demon Flags. A student from Bozhou's Xiahou High School who is secretly part of the Department of Night.

Ye Lanlan: Cousin of Ye Yan. Born in the Southern main branch family. Wields seven Demon Flags. Currently hospitalized after receiving radiation therapy to cure her cancer.

Bao Huajuan: A Nightwatcher guardian from a side branch Nightwatcher family. Wields one Demon Flag. A police officer in Bozhou's Police Department.

Ye Chong: The representative guardian of the Nightwatcher clan back in 1782. Born in the Northern main branch family. Wielded four Demon Flags. Was sent to resolve the Yun Zhonghe incident.

Three: A Nightwatcher from a main branch family. He was part of Sun, a secret organization plotting to obtain the Heaven Crystal by using the Department of Night. Wielded three Demon Flags.

Ye Liao: The representative guardian of the Nightwatcher clan back in 1860. Wielded five Demon Flags. He was part of the group that assassinated Che Yongtai's previous incarnation. Married to Xiahou Shan.

Ye Heping: Ye Yan's Nightwatcher training partner who died two years before the beginning of the story. Wielded two Demon Flags.

Trivia
Nightwatchers and their weapons are based off ancient Chinese night watchmen. They were responsible for reminding the time for the people who were still awake at night by sounding a gong they carry around at night with a mallet while yelling out the time. They were also responsible for catching thieves and warning of a fire if they happen to spot one.