Charyeok (차력 (借力), Lit. "Borrowing Power") literally means the act of borrowing strength from a "god" (can also refer to demons and human ghosts, not just literal gods). Charyeok is when someone makes a contract with a supernatural entity in which the contractor is able to borrow their power.
Most Charyeok are gained by the user proactively making the contract, and a "baptism" from another person with close contact to the gods may accelerate the process. A few forms of Charyeok though are implanted into the user or gifted from others.
Upon accessing that god's power, they're able to shape it (through their imagination and empathy) as their own unique ability. It appears that whenever Charyeok or divine power is used, it draws from the user's life/biological energy which appears as violet colored energy. Hence, if someone uses their Charyeok too long, they experience intense fatigue and other physical drawbacks.
Most characters in G.O.H have reached the level where they can materialize their Charyeok as a distinct, yet connected, living entity that they can control.
Charyeok varies greatly, seeing as how the way it appears depends on the entity giving power, the user's imagination and personality, as well as their own innate power/energy. Strength of Charyeok is measured in GP (God Points).
Na Bongchim claimed that serious injury to a body part, as much as a finger, could prevent Charyeok users from using their borrowed power, although Park Ilpyo was able to use his Charyeok while sustaining serious injury to his right eye during the national tournament. Shadow had also developed an Injector that makes Charyeok Users get ADHD and thus unable to concentrate enough to use Charyeok.
According to Dan Mori's observation, Charyeok with complicated activation requirement (either for the technique or the Charyeok itself), will relatively yield more power. Jung Mori also said that there is a small window where a Charyeok user is the most vulnerable, right before using their ability.
Long ago, humans, monsters, and gods lived on the ancient Earth, where landmasses were still forming and civilization had not yet arisen. The monsters sought to rule over the humans, whom were far weaker than they, and had not yet developed technology on a level to hurt them (humans were living in what would be considered the Stone Age). Mankind was divided and scattered, living in isolated clans, each trying to fend for themselves.
Eventually, a chieftess of a human clan named Ungnyeo appealed to the distant gods to lend them their power. They agreed after much deliberation, and thus Power Borrowing was born, giving the humans the power to defeat the monsters. However, this initial method of power borrowing had noticeable drawbacks eliciting Hwanung to eventually abolish the original power borrowing system, forever changing it into the Charyeok system that is currently present. Breaking the Taboo allows a Charyeok user to revert to the original method of Power Borrowing.
There are different ways that Charyeok manifests and is used, those various ways being divided into 7 classes, which are:
- Weapon Summoning and Reinforcement: As the name suggests this is when Charyeok is manifested as a force that the user summoned as their weapon and/or uses to bolsters their current weapon. A prime example for this is Na Hanseong's Aegis Shield. It is a weapon in its own right and can be used to increase the power of his sword. Other examples include Jang Jangmi's Bastard and Jin Pumgwang's Hammer.
- Hero Summoning: This is when Charyeok is manifested as a distinct entity or object which the user can control, usually based on a deity, hero or beast with a significance in human history. These entities/objects can also be 'equipped' to the user, altering their appearance and increasing their natural skills. These Charyeok may be invisible to all but the user, unless they choose to reveal it. Examples include King of the Earth and Haetae.
- Parasitic: This type of Charyeok manifests itself as an entity that lives on a part of the user's body, spreading and growing more powerful with every use. It is currently unknown what will happen if it completely spreads, but it is assumed that the user will gain vast power or be consumed by the entity. Examples of this type of Charyeok are Greed and Yamatano Orochi.
- Intuitive: This type of Charyeok is not based on existing objects or legends, but purely on the imagination of the user. It can be affected by the user's psychological state and relationships with others. Examples include Above and Beneath the Heavens, I Alone am the Great One and Dungeon Master – King of Babel.
- Direct Contract: As the name implies this is a contract in which a person is directly infused with power by the god, usually by contacting them within their own Realm. Direct contracts also allow the user to more efficiently communicate with the god who gives them power. It is the next level of current Charyeok widely used. Nine-Tails Guardian, Oxen King, Haetae, and Yeo-Po Bong-Seon are prime examples of this.
- Power Lender-ization/Lineal Descendant: A more advanced form of a direct contract, in which the individual receiving power becomes an avatar of the god and assumes their form, as well as gaining access to the full range of that god's power. This is only possible because the person receiving power is a lineal descendant of that god. Samuel Rosinante, Jose Natasha Violeta Alexandors, and Judge Q are all lineal descendants of a God with there ancestors being Heracles, Philip II, and Joker respectively.
- Key: A key is a rare and very powerful type of Charyeok which can seal and awaken abilities in mortals and gods alike. Aptly described as "the existence that will drag the gods from heaven", Keys are Charyeok born from intense hatred and wrath. The gods whose power is channelled are powerful entities that oppose the gods of heaven and seek vengeance against them. This hatred is one of the reasons why these particular Charyeok are so powerful. Pandora and Nine-Tails Guardian are prime examples of this.
- The Original Way Of Borrowing Power: A type of Charyeok that can only be used by those who break the Taboo. This is one of the most powerful type of Charyeok to exist because the gods directly infuse their godly energy into their contractor's body, with noticeable drawbacks such as the human who uses this type of Charyeok will either get older or younger. An example of the Charyeok in this category is Trinity: The Gods of the Wind, the Rain, and the Clouds
Prayer Awakening is a rare offshoot ability of Charyeok. While Charyeok is activated by the user concentrating their will in an attempt to draw power from the Realm of Gods that will warp reality through a mindset similar to praying, in the case of a Prayer Awakener that power originates from him/herself, allowing his/her greatest wish to be subconsciously manifested. Yun Taesu and Sakura Yui are examples of Prayer Awakeners.
List of Charyeok
Above and Beneath the Heavens, I Alone am the Great One is the Charyeok of Gang Daehyeop. It ignites a golden aura around him while increasing his physical capabilities, and going into higher level modes lets him use superpowers.
Aegis Shield is the Charyeok of Na Hanseong. It manifests itself as hundreds of floating, transparent hexagonal shards, with a light glow of biological energy. The user can telekinetically arrange these shards into any form they wish. Na Hanseong usually combines them to form the eponymous shield. However, he can also form it into full body armor or multiple blades.
Albatross is the Charyeok of Sin Taepung. It harnesses the air currents around him to throw wind attacks, shield against damage or allow flight.
Alpha & Omega
Alpha & Omega is the Charyeok of Jake River.
Adriadne is the Charyeok of Judge G. It allows her to control threads.
Ariadne's Thread is the Charyeok of an unnamed participant in the G.O.H. Consolation Match. It takes the form of vines that can be used to restrict the movement of the opponent.
Asura is the Charyeok of Romario Traviola. It is deemed as one of the most powerful Charyeok, and it's abilities include mind control, energy beams and attack reflection. Romario can also use the Original Way of Borrowing Power with Asura.
Bastard is the Charyeok of Jang Jangmi and Judge R. It appears as a large double-edged sword made of energy. It has incredible cutting ability strong enough to destroy the fighting ring.
Beelzebub is the Charyeok of Arangis. It increase Arangis' physical capabilities and lets him use God's Blessing.
Behemoth is the Charyeok of Judge Y. It generates a deadly poison around his fist that he can strike his opponents with.
Bruce Lee is the Charyeok of Xiaolin. It appears as Bruce Lee himself and provides the user with the fighting capabilities Bruce Lee had.
Charon is the Charyeok of Judge V. It transforms his jacket into black blades that can slice his opponents.
Chiron is one off the Charyeok that Park Mubong summoned using Project Wi-Fi. It uses a bow and arrow to deal long range damage.
Cube is the Charyeok of post-RagnarÖk Nox disciple Jacob. It can trap an enemy inside a box construct and, if a certain activation condition is met, drives the opponent into unconsciousness while analyzing their internal information.
David Copperfield is the Charyeok of Eric Sin. It gives him the power to use reflections of mirrors to generate a dimension where he is an illusionist on stage performing magicial stunts on his opponents.
Doppelganger is the Charyeok of Fei-Long. It was stolen by him from a Jeju Island team member. It gives the user the ability to take on the appearance and powers of others and can be used for different purposes including spying and ambushing. It also allows the user to make a clone of a person independent from the user. The user can make up to a 100 clones at a time.
Dragon Slayer is a Charyeok of Judge O. It is a power to command and control a dragon after beating it into submission. The user also gains several dragon characteristic, including fire manipulation and lizard-like eyes.
Dungeon Master – King of Babel is the Charyeok of Ban Sihyeon. It gives him the power to generate a dimension where he can terraform the environment into multi-storey Dungeons filled with monsters, with some monsters being able to be generated outside of the Dungeon.
Emperor Iskandar is the Charyeok of Alex. It greatly increases the user's physical power and let's them summon the steed of Iskandar, Bucephalus, which has the ability to fly.
Erysichthon is the Charyeok of Bang Jongjin. It gives the user increased physical capabilities.
Frost Hand is the Charyeok of Justin. It allows him to instantly freeze a variety of objects, and can solidify a blade of frost from his hand.
Garuda is the Charyeok of Fanimer. It can create poison and control human mind.
Gigantes is the Charyeok of Long-Shen.
Goibniu is the Charyeok of Judge D. It gives him the ability to repair things.
Golem is the Charyeok of an unknown person and later stolen by Jegal Taek's Charyeok, Greed. It has the appearance of a giant man made out of rock. It has great endurance and durability and is shown to be quite strong.
Golgoroth is the Charyeok of Judge E.
The Great Magician is the Charyeok of Jeon Jaesan. It allows him to cast a variety of magic spells.
Greed is a Charyeok that has been absorbed into Jegal Taek's body in the form of a living tattoo on his left arm. In its true form, it takes the form of an enormous shadow with large teeth and hundreds of blood red eyes. It appears that Greed can call forth all the Charyeok's of the persons it has eaten from before. This grants Taek all of the powers of each individual Charyeok to use at will. Jack the Ripper and Mage are included among them.
Original Greed, as the name implied, is the original greed created by The King for the sake of attaining immortality. The last user who is born with it is Ultio R. The main difference between this variant is this one has superior Erosion, making it capable of eating all things on earth.
Gryphon is the Charyeok of Violeta. it takes the form of half bird-half mammal creature with body like a horse/lion and legs, wings, and head of an eagle.
Guardian Angel is the Charyeok of Han Yewon. It allows her to shield others from harm.
Haetae is the Charyeok of Han Daewi. When shown in its full form it takes the shape of a blue dog-like creature with multiple fangs, a big nose and eyes, and a top hat. Its is shown to be a powerful Charyeok but due to the contract being with a baby it's full abilities are limited, at least until it takes matured form in Direct Contract.
Hammer is the Charyeok of Jin Pumgwang. It materializes as a large hammer with one flat end and the other end is somewhat broken. The hammer can be used to attack opponents with sheer brute force.
Hattori Hanzo is the Charyeok of Judge C. It grants the user many ninja related skills, like cloning, afterimages and disguising.
Heavenly King Chiyou
Heavenly King Chiyou is the Charyeok of Chiu Byeolak.
King of the Earth – Metal Head
King of the Earth – Metal Head is the Charyeok of Chiu Bi.
King of the Sky – Ruler of All
King of the Sky – Ruler of All is the Charyeok of Cheonhain.
Hercules is the Charyeok and lineal ancestor of Samuel Rosinante. Hercules is one of the strongest Charyeok shown in the series. It boosted the user's physical strength to epic proportions, as it enabled the user to briefly hold a copy of Ruyi Jingu. When powerlenderized, the users strength is enhanced even further as it can prevent the copy of Ruyi Jingu from enlarging itself simply by gripping on it.
Hipparchus is the Charyeok that Joanne and Dr. Schmitz used to telepathically transmit knowledge.
Hui Mori is the Charyeok of Jin Mori. It takes the appearance of the deceased clone of the Monkey King. It increased the user's physical capabilities in addition to supplementing his technique's with Hui Mori's own.
Icarus is the Charyeok of Dae Baegho. It has the ability to levitate objects around him by giving them wings which appear unseen to everyone except Dae Baegho himself.
Ifrit is Charyeok of Priest Zig. it takes the form of muscular humanoid fire spirit. It imbued the user with fire power.
Jack the Ripper is the Charyeok of Gwum Gi. It looks like a middle aged man with a long mustache, wearing a hat and long coat. It gives Gi the ability to form blades to attack the opponent. The Charyeok can also use its body to form blades to attack an opponent at close range.
Jeanne D' Arc is the Charyeok of Andre Oscar. It takes the form of the historical heroine of France during hundred years war. It was the original owner of Andre's national treasure The Rapier of Jeanne D'Arc. This Charyeok has two phases. One increased the strength of an attack and the other enhanced the attack with fire.
Jebe is the Charyeok of Priest Fangwu. It takes the form of a mongolian general that served Genghis Khan. It was the original owner of his National Treasure, Jebe's Bow. A combination of single arrow fired by this Charyeok and one fired by Fangwu with Jebe's Bow managed to crack the door to central control of Nox.
Jihad Doll is the Charyeok of an unnamed Nox follower. It generates an exact replica of a person that can be used as a walking bomb.
Joker is the Charyeok of Judge Q. It carries a scythe and has a smiling face. The joker can be summoned from the deck of cards Q carries with him. The Joker can manifest from any of the many cards that Q uses to fight. It's scythe is quite sharp, and Q himself can also wield it, not just the Joker.
Jupiter is the Charyeok of Natasha, it's form is unknown. One of the abilities it gives the user is shield generation.
Kabbalah is the Charyeok of Xiaochen. It is centred on providing protection for the King.
Kamaitachi is the Charyeok of Nagisa Midori. It takes the form of a massive weasel with three tails.
King of the Earth is the Charyeok of Sang Man-Duk. It can summon nephilims and blades the size of skyscrapers. Man-Duk can also use the Original Way of Borrowing Power.
Kingdom Armoury is the Charyeok of Samson.
Koniecpolski or Winged Hussar is the Charyeok of Aldon Ski. It takes the form of a Polish cavalry but its powers are unknown.
Kraken is the Charyeok of Lee Marin. It can absorb the Charyeok of the opponent and convert it into HP, thus helping the user regain his stamina.
Kuafu is a Charyeok that Park Mubong used using his Wi-Fi project. It attacks the opponent directly with its drill-like hand and massive size.
Lion is the Charyeok of Ju Seokho. It takes the form of a blue lion.
Longinus or Longinus' Hand is the Charyeok of Park Mubong. It can summon a massive hand that can devastate an area as well as gives the user limited control over gravity. It also provides the user with a shield. It was the first Charyeok to appear in the series, appearing in Chapter 1.
Mage is the Charyeok of Jeon Jugok. It's appearance is that of an old mage wearing a hat and holds a staff in its hands. Jugok can use elements like fire and lightning to attack the opponent.
Marionette is the Charyeok of Judge P. It can be used to manipulate people as puppets by attaching strings to them.
The Master of the Sky or Thunderbird is the Charyeok of With Hawk. It takes the form of giant bald eagle but its powers are unknown.
Megalodon is the Charyeok of Jegal Taek. It has the appearance of a large shark. It was used to attack and pierce the opponents body with its fangs. It can also summon fangs separately to attack.
Michael Jackson is the Charyeok of Mohamed Al Halim.
Midas or Midas Touch is the Charyeok of Ulv Sylvester. It gives him the power to turn his enemy's bodypart to gold if it sustained enough damage.
Mind Snatcher is the Charyeok of Violet Ella Wong Perez. It lets her read the thoughts of other people, and also steal use the Charyeok of other Charyeok Users.
Mirror of Narcissus
Mirror of Narcissus is the Charyeok of Judge IV. It can bend the direction of ranged attacks.
Mithril is the Charyeok of Kane.
Mud Golem is the Charyeok of Priest Malchik. It enabled the user to created mud constructs of varying sizes depending on the need.
Narcissus is the Charyeok of Peach. It can project images and Charyeok.
Necromancer is the Charyoek of Jwa-Woo. It takes the form of grey skeleton wearing purple hooded robe. It allows the user to summon an undead creature that can turn people into something similar to itself through touch or bite.
Nine-Tails Guardian is the Charyeok of Park Ilpyo. It is the first key to be introduced in the series. It is currently one of the few Charyeok that changes the appearance of it's user, besides Yu Mira's Yeo-Po Bong-Seon. It gives the user a small amount of HP upon appearance. It greatly enhances all of it's user's physical attacks, speed and power to the point where it can no longer be traced with the naked eye. It also allows the user to summon many nine tailed foxes ranging from big to small. It also grants the user the ability to create and manipulate fire at will.
Nymph is the Charyeok of Kay. It gives him the power to lower the ignition point of wherever he heard a sound, making it visually similar to pyrokinesis.
Besides this there is also a Charyeok with similar name used by Park Mubong. It can deal long range attack using it's voice.
Ono no Michikaze
Ono no Michikaze is the Charyeok of Judge F. It can summon Hanafuda cards that generate a variety of abilities.
Oxen King is the Charyeok of Baek Seungchul. It is the second Direct Contract-type Charyeok to be introduced in the series. Seungchul is in a direct contract with half-ghost King Uma. By using this contract he is able to fight against foes like the heavenly princes. It is currently one of the few Charyeok that changes the appearance of it's user, besides Yu Mira's Yeo-Po Bong-Seon. It greatly enhances all of it's user's physical attacks, speed and power to the point where it can no longer be traced with the naked eye.
Paladin Siegfried is the Charyeok of Moon Giju. It summons Walmung and parts of armor around him which is capable of great destruction. It enhances his fighting ability and he can use many high level attacks.
Pandora is the Charyeok of Lee Sujin, this is the second key introduced in the series. Like the other key, it changes the appearance of the user. This Charyeok originated from Pandora from the Greek myth, the woman who opened the Pandora's box and let loose all the evil and suffering in the world. She can create disease and illness wherever she goes and she seems to have a power to produce poison from her body.
Pazuzu is the Charyeok of Zamila. It takes the form of a large human-arachnid hybrid and grants the user improved speed and strength.
Perun is the Charyeok of Denisovich. It takes the form of the Slavic thunder god, similar to Zeus.
Phoenix is the Charyeok of Judge B. It takes the form of a large blue bird. It is a Charyeok that eats the life force of its prey to create new birds.
Prayer Realisation is the Charyeok of Abel. It lets him grant the wishes of others and make them Charyeok Users.
The Princes of Natak or Three Princes of Natak is the Charyeok of Dan Ahan. It's appearance is the deceased Three Crown Princes. It can be used to increase the physical power of the user and allows manipulation of Three Elements: Ice, Earth, and Magma.
Raven is one of the Charyeok Park Mubong summoned using project Wi-Fi. It's part of long ranged dealing attack Charyeok. 
Sadie is the Charyeok of Priest Saturn. It has the appearance of a woman with her eyes covered. It uses the enemy's shadow to summon hands to attack. It can summon a whale like creature to attack from behind.
Saint George Ascalon Sword is the Charyeok of an unnamed participant in the G.O.H. Consolation Match. It creates appendages off of the arms of the user that can be used as a substitute for a sword.
This unnamed Charyeok is used by Oh Seongjin. It takes the form of a man in heavy red samurai armour wielding a sword. It can be presumed that this Charyeok increased the strength of its user.
Sapsal Dog is the Charyeok of Shim Bongsa. It has the appearance of a large black dog with a thunderbolt on its forehead and three tails. Its abilities are unknown other than that it is capable of flight.
Secret Gun Closet is the Charyeok of Vincent. It allows him to conjure out whatever weapon he wishes from nearby containers.
Seonbi Dragon is the Charyeok of Cool Guy. It's abilities weren't shown.
Shield of Discrimination is the Charyeok of Priest Axley Ivanovic. It is a pair of shiny white wings. Just as the name suggests, these wings can shield opponent's attacks. The Charyeok provides the ability of flight. It is shown that the wings can't be regenerated after being cut.
Siren is the Charyeok of Myeong Moondae (imposter). It has the shape of a bat and just like a bat, it can generate sound waves which can be heard only by the victim. These waves can cause a weaker person to feel nauseatic and make them to collapse.
Soul Eater is the Charyeok of Hajime Ryo. It allows him to drain the bio-energies of other Charyeok Users into himself to increase his physical strength.
Succubus is the Charyeok of Sakura Yui. It lets her exact mind control on all males of every age, with only a few exceptions able to resist doing her bidding.
Thanatos is the Charyeok of Drake McDonald. It has the ability to create a silk-like substance which it uses to sew cuts and wounds close, as well as sew dismembered body parts back on while also allowing him to regenerate over and over. It also gives the user wings.
Third Eye is the Charyeok of Packman. It allows him to peek into the private lives of others.
Thor is the Charyeok of Anna. It takes the form of the Norse God Thor and grants the user the ability to levitate themselves and other inanimate objects as well as shoot laser beams from their eyes.
Thunder Dragon is the Charyeok of Sunny. It takes the form of asian green dragon with two horns. It allows its user to manipulate electricity. Thunder Dragon is also the only Charyeok shown this far whose contractor uses Boost Surgery, allowing it to acquire the fire attribute.
Trinity: The Gods of the Wind, the Rain, and the Clouds is the Charyeok of Kim Ungnyeo, its true form is unknown other than three light-like particles orbiting around her. This Charyeok allows her to manipulate weather-related phenomenon. Ungnyeo can also use the Original Way of Borrowing Power.
Umdiji is the Charyeok of Mujahedin. Its true form is unknown. It grants the user the ability to control the opponent's perception through the usage of hallucination.
Undine is the Charyeok of Judge U.
Uriel is the Charyeok of John. It grants the user the ability to fly and increase their physical strength.
Verdandi is the Charyeok of Dean Ockham. It gives him powers of precongition and other time-based abilities.
Virtues Dunamis is the Charyeok of Maria. It takes the form of a female angel with unknown powers.
Void is the Charyeok of Judge K. It gives him the ability to manipulate space.
White Shark is the Charyeok of Yun Taesu. It can summon fangs inside an opponent’s body to rip them apart from within, or take the form of skeletal sharks that swarm in on opponents.
Wizards is a Charyeok that Park Mubong summoned using project Wi-Fi. Based on it's name, it could be one of the Charyeok that enhance magic. It's part of long-range damage dealing Charyeok. 
Xiang Yu is the Charyeok of Li Shuwen.
Yamatano Orochi is the Charyeok of Kusanagi Kyoichi and every previous firstborn son of Kusanagi Clan. In addition to enhancing their fighting ability, it also allow the users to summon snakes, including the legendary demon, Yamatano Orochi itself, and grant him several snakelike ability. The user risks losing control of his own body if this Charyeok is used too much.
Yeo-Po Bong-Seon is the Charyeok of Yu Mira. It enhances her fighting ability and she can use many high level attacks. It also enhances her swordless sword styles. It is one of the few Charyeok to change the physical appearance of its contractor. As of late, it is a direct contract-type Charyeok.
- It was hinted that it was Kim Ungnyeo and Hwanung's child that spread Charyeok among humans, in order to create a better world for humanity to live in, as per the wish of Hwanung.
- In the original myth, Hwanung's son with Ungnyeo is Dangun, the legendary founder of Gojoseon, the first Kingdom in Korea. If one were to go by this myth, it would greatly infer that Dangun was the one who spread Charyeok all over the world in the God of High School series.
- The history of how Charyeok came to be is a political reference to how the USA, using North Korea as a bogeyman, blackmailed South Korea into purchasing US weaponry at outrageous prices through exorbitant sales contracts and unequal military treaties.