In the form of All the World's Evil within the Grail, Avenger doesn't have a true sense of self. "It" can be said to be lost in an abyss of shallow slumber within darkness sealed in the bottomless earth. It only dreams of the endless "prayers", unreasonable and unattainable, that the human had long ago been entrusted. It only knows that some sort of sudden changes happened that placed it within the Grail that is "like a mother's warm placenta." It is only waiting for the moment of its coming birth, so it searches for opportunities to manifest into the world.
Avenger, in its pure form as All the World's Evil, reacts to Kiritsugu Emiya's statement "For that, even if I am to carry 'all the evils of this world' – it won't matter. If that can save the world, then I'd gladly accept it." while he is arguing with Saber after the deaths of Lancer, Kayneth Archibald El-Melloi and Sola-Ui Nuada-Re Sophia-Ri. Hearing that it has been called by someone, it wishes to answer him as soon as possible. While waiting for the "birth canal", the Holy Grail, to open, it dreams of the cries that will dye the world crimson red.
After Irisviel von Einzbern's death, Avenger records her personality at the time that the soul and conscience of Irisviel merged with the Greater Grail, assuming her form in order to communicate with Kiritsugu after he is drenched in the Grail Mud. Avenger, now as Irisviel, claims that the record is unmistakably genuine, as the last thing that she touched before her demise was All the World's Evil. It inherited Irisviel's last desire by personifying her wish to "remain this way."
During the final battle between Kiritsugu and Kirei Kotomine, the Grail gushes out black mud which engulfed both of them. Though both of them entered in a dream like state, the Grail recognizes Kiritsugu as the victor. Avenger uses Irisviel to confront Kiritsugu in his mind and asks his wish, however it comes with a heavy price. In his mind, he was forced to confront the fact that his methods who practiced in all his life will eventually lead to him becoming the ultimate enemy of all humanity, equal to Angra Mainyu itself - and, 'Irisviel' proclaimed, this path is correct.
Kiritsugu, now realizing that the Grail is corrupted, shoots down all his loved ones, including the illusions of his wife and daughter. As he rejects and strangles 'Irisviel', Avenger places a curse on him - to never be free of regret until his painful death.
Kirei, having went through the same experience, questions Kiritsugu why he rejected the Grail; Kiritsugu's answer being that it sacrifices too many things for what it gives. Kirei says that he wanted it even so and Kiritsugu, admitting that he did not understand Kirei, shoots him in the heart.
In Kirei's last moments, the Holy Grail appears to him in his mind. Filled with hatred and envy for Kiritsugu, Kirei reaches out and touches the cursed artifact. He prays for an end to humanity before his death and his wish is granted in the form of the fire. Meanwhile, Avenger's emergence is prevented by Kiritsugu, who commanded his servant, Saber, to destroy the Grail upon recognizing the evil presence emanating from it. However, she only destroyed the vessel and not the contents - the 'black mud' - which spilled out from its core onto the streets below and caused a fire that eventually destroyed a large part of Shinto. The black ichor managed to soak Kirei's lifeless body, resurrecting him with an artificial, black heart. Gilgamesh was covered and absorbed into the black mud that poured out when Saber destroyed the Grail's vessel.
In the original light novel, there is a scene where Gilgamesh is contacted by Avenger inside the black mud that came out of the Grail. Avenger reveals the ugliness and hatred of the world, but to his surprise Gilgamesh accepts this and acknowledges his role in carrying the burden of the world. Gilgamesh's strong ego helps him fight off Avenger's influence and the black mud ejects Gilgamesh.
Kirei wakes up and finds Gilgamesh near him. He seemed to have gained a flesh body from something that flowed to his body through the Master and Servant connection.
At the end of the Fourth Holy Grail War, Zouken Matou acquired the fragments of the Grail. He synthesized it with his Crest worms, which he put inside the body of Sakura Matou. Though she was incomplete, this turned her into a second Lesser Grail.
Shirou Emiya confronts Kirei Kotomine who already has access to the Holy Grail. Kirei reveals that Avenger is inside the Holy Grail cursing on the human world. Due to having his heart replaced by Angra Mainyu, he has an affinity with it and the black mud from the Grail which he uses in an attempt to curse Shirou. Shirou demonstrates his mental strength by resisting the curse at close range and projecting Avalon to shield himself from the corruption. After Kotomine and Gilgamesh are killed, Shirou and Saber destroy the contents of the Grail, ensuring the malice within it will never be used again. Due to the way the events of 5th Holy Grail War ended with the Grail having been completed by obtaining the souls of seven Servants at the end of the conflict and Avenger having reborn in the form of this Grail in end of this route (something that does not occur in the routes of Unlimited Blade Works and Heaven's Feel due to the circumstances of how these two routes ended and their endings), this caused in one of the possibilities in that the events of Fate/hollow ataraxia to happen in case the soul of Avenger had survived the destruction of its physical vessel and was disconnected from the Greater Grail to look for someone who had any desire to be fulfilled.
Unlimited Blade WorksEdit
Gilgamesh implants Illyasviel von Einzbern 's heart into Shinji Matou to turn him into the Lesser Grail, and Avenger uses Shinji to manifest as a bloated mass of flesh and black mud. Rin Tohsaka manages to extract Shinji from Avenger's manifestation, and Saber uses Excalibur to destroy the deformed Grail. Attempting to claim Gilgamesh as a host following the loss of his incomplete vessel, Avenger creates a black hole that is able to disrupt Shirou's Reality Marble and absorbs Gilgamesh. However Gilgamesh uses his Enkidu chain to attach Shirou, protesting that Avenger cannot use him as a core because they are both Servants. Archer tells Shirou to duck and kills Gilgamesh with an arrow; and Gilgamesh's body is consumed by Avenger, causing the black hole to disappear. In the 2014 Unlimited Blade Works anime adaptation, Avenger's imperfect manifestation takes the form of a humanoid torso before transforming into the bloated mass once the ritual begins; attempts to grab Gilgamesh after Shinji is extracted before being repelled by Enuma Elish; and transforms back into a humanoid torso before destroyed by Saber's Excalibur. In this version, it also took on Irisviel's form to manipulate Illya by telling her that Kiritsugu killed her mother in the fourth Holy Grail War, according to the flashbacks.
Avenger emerges during the Fifth Holy Grail War in the Heaven's Feel route in an attempt to be born into the world as an incarnation of All the World's Evils. He forms a contract with Sakura Matou, who has been made to act as the vessel for the Grail; and manifests as the Black Shadow before blackening her into Dark Sakura. She is confronted by Rin in the chamber of the Greater Holy Grail beneath Mount Enzō, her power equally matched by The Jeweled Sword of Zelretch. Rendering Sakura's shadows useless, Rin makes her way to Sakura, but is unable to give the finishing blow due to her love of her sister. Rin embraces Sakura even after Sakura has stabbed her in panic. Realizing Rin's love, Sakura again starts resisting her evil long enough for Shirou to dispel Angra Mainyu's grip on her soul with Rule Breaker. In the Normal ending, Shirou does trace Excalibur and destroys the Grail, but his life extinguishes soon after. Sakura, refusing to accept Shirou's death, continues to live in the Emiya household, forever waiting for Shirou; when she herself had passed away Shirou finally arrives amidst the sakura trees waving to her. However, in True ending, Ilya intervenes, closes the gate for good, and performs the Heaven's Feel on Shirou to keep him alive.
- Main article: Avenger (Fate/hollow ataraxia)
Avenger makes a brief cameo appearance in the last episode of Carnival Phantasm, he also appears in a glimpse in the EX season episode.
In the Fate/Apocrypha universe, the Einzbern during in the Third Holy Grail War had two options to pick their Servant. The first option was to alter the system of the Greater Grail itself and summon Angra Mainyu to a unique Avenger-class Servant. The second option was to abuse one of the systems installed in the Greater Grail by summoning Amakusa Shirou Tokisada as the ultimate Ruler-class Servant, meant to be an impartial authority whom regulated the progress of the War. They would then make use of the great privilege possessed by Ruler: its Command Spells for the other Servants. They were in conflict between choosing brawn or brains. After much contemplation, the Einzberns chose Ruler. One could say that they picked the safer option; perhaps their previous defeat had robbed them of their confidence in powers higher than they. Unlike Avenger, Ruler was the last servant to survive in the Third Holy Grail War and he survived for the next sixty years. Ruler wished for humanity salvation and wished the happiness of all mankind, for innate goodness to be found in the heart of all humanity and the annihilation of Angra Mainyu: All the Evils of the World.
In the Fate/Extra universe, Angra Mainyu/CCC is the anti-planetary Noble Phantasm of the demon-transformed Kiara Sessyoin. Her existence is similar to Avenger who had once been demonized and celebrated as a sacrifice to prove the evil of mankind.
The alignment of being Angra Mainyu: All the World's Evil (この世全ての悪, Kono Yo Subete no Aku?) is a curse that had put all of the evils in the world on one person, that who became Angra Mainyu. It is not a very useful ability, as it only grants the Servant's soul an alignment directed towards killing people even after when it takes on the form of directionless and alignmentless magical energy after losing the shell of its class. Normally it would not affect anything, but with the way the Great Grail is set up to take the Servant's souls means placing "All the World's Evil" into a wish granting machine.
After Avenger is absorbed during the Third Holy Grail War, the Grail is transformed into an incarnation of Angra Mainyu that materializes as black mud and later a large humanoid under certain conditions. The materialization of Angra Mainyu brought forth by truly opening the Holy Grail is an ichor that will consume every human being, 6 billion curses flowing out from the gate to hell. Gilgamesh specifically mentions 5.6 billion curses for an unknown reason. It is a reaper that will strike down all humans equally, an endless darkness that is born from humans and massacres them.
Ichor leaks from the Grail when it is first being established. Its nature is a curse so strong that it is visible, so it can be called magical energy specialized for destroying people. It can not be practically used in any way, as it cannot be reshaped or anything of the sort. It stains anybody it touches with a strong curse and melts them as if they were being digested. The pain and fear felt before death remains as magical energy and becomes the next curse to seek out living people. It will kill anyone it touches unless they can remove it from their body before they are melted away. Those who are not dissolved will be assaulted mentally by "All the World's Evil", eventually going insane or left cursed by its after effects, such as Kiritsugu Emiya, who lives for a number of years while suffering under the curse until it causes his death.
If fully submerged in the curse, it paints space itself around the person, surrounding them in darkness and imprinting hell upon their brain by showing them unseeable darkness, ugliness that can't be acknowledged, and all the crimes of the people in the world that make them want to run away from it all. Those trapped with the darkness will eat themselves to death from pain and hatred, and they will be swallowed by it like the painted space. Avoiding such a curse and the very concept of blocking it are nearly impossible. Escaping should be impossible, so Kirei Kotomine is shocked that Shirou manages to do just that through only willpower.
Servant affected by the mud can be blackened.
 Fate/complete material III: World material - Record of Heavens Feel - Holy Grail War: History of the Lesser Grail, p.009
History of the Lesser Grail
• Fourth Holy Grail War
• Fifth Holy Grail War
• Matou Sakura
In the final events of the Fourth Holy Grail War, Zolgen (Matou Zouken) acquired the fragments of the destroyed Grail. He combined the fragments with his Crest worms, which he put inside Sakura's body. Though she was incomplete, this turned her into a second Lesser Grail.
 Fate/EXTRA material - Encyclopedia: All the World's Desire [Noble Phantasm], p.158-159 [T]
All the World's Desire [Noble Phantasm]
This is the anti-planetary Noble Phantasm Kiara gains after her reincarnation.
Angra Mainyu is the most self-serving heinous Noble Phantasm of them all where Kiara uses the world to masturbate.
Kiara offers her body in a sexual manner to all living things on Earth, including humans, animals, and plants. By completely accepting all people as is she gains the greatest possible mastery over their senses and carnality.
This Noble Phantasm is derided for being demonic and it’s similar to the living sacrifices used for certain artificial magic ceremonies used the past in order to prove the evil of humans.
It is a vortex of pleasure that melts all sentient beings, and digests their “life” in an instant. While in reality it all happens in an instant, but it feels like an eternity of pleasure.
Regardless of how different the structure of a beings intelligence may be, this vortex affects all without exception. It is not a Noble Phantasm that is limited to affect only those on Earth.
The damage increases if certain conditions are met.
If the target is of the opposite sex, the damage increases.
The more intelligent a being is, the more damage it does.
As far as the setting and lore are concerned, the Servant who would be hit with the least damage would be Archer, and Gilgamesh would be damaged the most.
The reason why this attack’s power, visuals, and scale are so huge is because reincarnated Kiara is a being similar to Saver.
People who devote their life to bringing salvation to Sattvas (living things) are referred to as Bodhisattvas. People who have attained moksha (libertation/release) and become Buddhas are also Bodhisattvas. A Bodhisattva is a god of universe scale and power, and can easily manage things on the scale of the Solar System.
Buddhism has a sense of scale of the universe that stands out from that of other religions. There are concepts like Nayuta (1060) and “The Infinitely Vast Number” (1068) which were created to represent the scale and size of a Buddha.
The entire universe is the domain of a Buddha. In Buddhism the universe in considered to be made up of three billion solar systems (a great trichiliocosm). A galaxy comprises of 3000 solar systems (a small trichiliocosm), and 1000 small trichiliocosms make up a trichiliocosm.
This actually aligns with the real scale of galaxies, galaxy clusters, and super clusters.
India had this stuff figured out over 2000 years ago? Holy crap!
In the initial design phase of the game I submitted some paperwork describing this Noble Phantasm. I thought there would be no way that this gets by CERO untouched, but surprisingly enough it did.
I still have no idea how this was able to make it past them.