Originally, Ryu scarred Sagat with a single Shoryuken in the original Street Fighter game. That story element was later retconned in Street Fighter Alpha that Ryu lost control of himself and his rage by rising up fist first, scarring Sagat with a Metsu Shoryuken instead. His attack took on the properties of Goutetsu's original art, despite having never been taught it by his master Gouken. Although Sagat wanted revenge for his scarred chest, he never knew that the scar came from something that had awakened the darkness inside of Ryu until the events of Street Fighter Alpha 3. Ever since then, Ryu has had a massive struggle against the Satsui no Hado's influence over him throughout the series' storyline.
During the events of Street Fighter V, the Satsui no Hado within Ryu was being called out by the consumer of souls. However, in the end, Ryu managed to control and overcome the Satsui no Hado inside him by tapping into the Power of Nothingness.
The Satsui no Hado is a form of ki that is rooted in the darker aspects of the natural human instinct (including the desire to survive, trample, and impose over opposition), and on a metaphysical level, the natural occurrence and manifestation of loss, decline, and destruction.
To tap into the Satsui no Hado, a person must be so consumed with the desire for victory and perfection, be close to death, or else possess such intense rage and hatred, that they are willing to kill. As such, only people who push themselves to be the best at any cost can take full advantage of it, however, the untrained mind can be driven into insanity if they are not mentally ready for it. Learning the Satsui no Hado is the first step in learning the most fatal technique known to all of their martial arts - the Shun Goku Satsu, also known as the Raging Demon.
Physical and Mental Changes
For the people who do succeed in harnessing it, they become extremely powerful, but at the cost of losing their humanity and compassion; they develop a cold, negative outlook on life, a nihilistic detachment from themselves, as well as other people, and develop an obsessive, dark, murderous, and even suicidal desire to fight.
The user also gains the ability to sense, float, and potentially influence, the emergence of the Satsui no Hado in others. Once a user has tapped into the Satsui no Hado within them, it can be very difficult to resist conflict. Within the main series, Goutetsu is the only person known to date that was able to balance its power without completely giving in to its evil.
When under the Satsui no Hado's influence, a person's eyes will glow red and their teeth will extend into sharp fangs. If one embraces it to a lesser degree, their eyes will glow blue. If one balances the Satsui no Hado and the Power of Nothingness, they will be in complete control of their power; however, if one has used it to their fullest extent for too long, they cannot be released from its hold and will transform into a demonic entity, likely one similar in appearance and personality to Oni.
Street Fighter characters
Goutetsu himself was once seen meditating while tapping into the Satsui no Hado, so he probably encouraged or at least accepted it, but he did not lose his humanity like Akuma. This is likely because he only used it sparingly and wisely, which is why he kept his human facial appearance and did not demonstrate signs of corruption. This was also how both of his students, Gouken and Akuma, were introduced to its power.
Goutetsu must have taught Satsui no Hado to his pupils if he also taught them the Shun Goku Satsu. However, Ryu (only while under the influence of Satsui no Hado) can use this technique despite the fact that Gouken never taught it to him, thus implying that the technique is an inherent quality of the dark power.
Once Akuma fully gave in to the Satsui no Hado, he lost all of his human emotions, and was solely motivated by violence
Goutetsu was initially pleased and somewhat impressed with Akuma for tapping into Satsui no Hado during a life or death battle for control of their school. Akuma wanted to tap into the Satsui no Hado to become more powerful, and wanted to use it to kill people he found "worthy", rather than using it for enlightenment and good like mentor. Goutetsu may have been unaware of his student's descent into madness.
However, Gouken developed a alternative derivation of the style by removing the dark power out of fear and disgust for the Dark Hado, as he believed it to be inherently evil, as a result of seeing how Akuma used it to murder Goutetsu. He condemned his brother for corrupting his Hado no Chikara (波動の力 Hadō no Chikara?, "Surge of Power") and vowed to never teach it to anyone.
Although Akuma may have "mastered" the Satsui no Hado, he could not stop the side effects of this dark force, although it is highly likely he had no desire to. His understanding of the Satsui no Hado is so great that he can embrace it to a much lower degree, giving lesser opponents a fighting chance. However, he still cannot return to human form, as he has used it to his fullest extent for too long.
Oni is the result of Akuma fully merging with the Satsui no Hado. As explained earlier, his appearance has changed to that of a larger, demonic creature with a supernatural power beyond that of Shin Akuma. At this point, he has become a marauding berserker willing to kill anyone and anything, especially if he deems someone as a greater evil, such as Bison and Seth.
During Street Fighter Alpha 2, Ryu finally realized that the Satsui no Hado was the culprit behind his aforementioned victory over Sagat. Ryu vowed to reject the Satsui no Hado, because he knew that he could not control this dark force, and thus could not risk killing anyone he fought or losing his compassion and humanity.
Although Ryu never shows any signs of the Satsui no Hado's influence after the events of the Street Fighter IV series, several games present a hypothetical version of Ryu who has embraced the power, willingly or not, becoming Evil Ryu in the process. Furthermore, other media often depicts him temporarily succumbing to the Satsui no Hado and assaulting an opponent before returning to normal.
It was not until the end of Street Fighter IV that Gouken was able to seal it away using the "Power of Nothingness" to help him control it like Goutetsu; however, it is unknown how long the seal will be able to hold his dark power. A demonic version of Evil Ryu appears in the Arcade Edition of Super Street Fighter IV with an appearance similar to that of Akuma, possibly to show how he would transform if the seal was broken.
In the UDON comic book series Street Fighter Unlimited, Ryu finally attained complete control over the Satsui no Hado by entering a state he calls "Shin Ryu" (Shin meaning "True" in Japanese). This state allows Ryu to safely harness the Dark Hado by merging it with the Power of Nothingness, bringing balance to his light and dark ki. As Shin Ryu, he was able to finally defeat Akuma. Ryu's appearance in this form is mostly the same, the only noticeable changes are to his left eye, which glows red, as well as the occasional flare of a red and blue aura.
In the events of UDON's Street Fighter Legends: Sakura comic, Dan falls to the dark power while fighting Sakura. However, Dan's attempt to perform the Shun Goku Satsu on her fails by resulted in him tripping over her backpack and rendering himself unconscious by Sakura's attack.
Dan has a different kanji appearing on his back, showing the kanji (父 chichi?, "father"). It is possible Dan's power stems from the feelings of hatred that he harbours towards Sagat for murdering his father.
Despite Dan's paltry skills, Gouken is well aware that such power can manifest to anyone, especially with a vengeance-motivated man like Dan, and become a proper threat in time, which is why Gouken expelled him from his dojo and deprived him of proper Ansatsuken teachings.
In UDON's Super Street Fighter comics, Sakura actually falls to the influence of the Satsui no Hado while fighting Akuma but loses it thanks to Ryu absorbing it.
In Marvel Super Heroes vs. Street Fighter, there is a secret character known as Dark Sakura (also called Sunburnt Sakura), a version of Sakura who utilizes a mixed moveset of Akuma and Evil Ryu. Despite her abilities, this form of Sakura does not use the Satsui no Hado, as referenced by her article on the Shadaloo Combat Research Institute database. Instead, she is angry because she got a sunburn.
In her normal forms, she also uses a variation of the Shun Goku Satsu that is not fueled by the Satsui no Hado, as seen in Rival Schools and Street Fighter EX series.
According to F.A.N.G, in the story of UDON's Street Fighter Legends: Cammy comic, Juri's Feng Shui Engine is actually a gateway between Psycho Power and the Satsui no Hado that Shadaloo's scientists have been secretly studying for M. Bison that can be used for warfare.
Characters from other media
In UDON's Street Fighter Origins: Akuma comic, Akuma and Gouken's late father, who is named Gyūki ("Ox Oni"), used the Satsui no Hado to murder the leader of a bandit gang.
In the Street Fighter × G.I. Joe comic, G.I. Joe character Jinx apparently uses the Hado as well.
In the crossover game Marvel vs. Capcom: Infinite, Thanos built a containment device in Abel City. This device, a gauntlet of sorts, gave Thanos the ability to drain Ryu of the latter's Hado, which gave Thanos the power to wield the Satsui no Hado by artificial means, presumably with far better control and without the consequences of wielding it.
In Street Fighter vs. Darkstalkers, Belial was able to use this power to stop Jedah from overthrowing his title as a king.
In Street Fighter X Tekken, Toro is said to have the Satsui no Hado in him.
In Street Fighter Alpha: The Animation, Shun used the Satsui no Hado when fighting.
In Street Fighter Alpha: The Animation, Sadler was able to gain the Satsui no Hado from Ryu with his technology as a means to rule the world.
Known victims of the Satsui no Hado
Street Fighter games
- Sagat - Defeated and accidentally (and presumably unintentionally) scarred by Ryu's Metsu Shoryuken.
- M. Bison - Defeated and seemingly murdered by Akuma's Shun Goku Satsu in Super Street Fighter II Turbo, but survived the attack by putting by a part of his Psycho Power in another body.
- Gen - Akuma used the Shun Goku Satsu on Gen during their fight in Street Fighter Alpha 2, but it had no effect on Gen since he had emptied his soul beforehand. In Street Fighter V however, Akuma returned to fight Gen again after realizing he had beaten his illness, thus deeming him worthy to kill. He defeated Gen with the Shun Goku Satsu after years of training harder.
- Gouken - Defeated and seemingly murdered by Akuma's Shun Goku Satsu, but survived by emptying his soul using the Power of Nothingness.
- Gill - Though disputed whether canon or not, he was defeated and seemingly murdered by Akuma's Shun Goku Satsu in Street Fighter III, but recovered via resurrection.
- Lee - Defeated by Akuma in Street Fighter Origins: Akuma.
- Cody - Defeated by a possessed Ryu in the Street Fighter II Turbo comic.
- Rose - Attacked by Akuma in an effort to save Ryu from Bison in the Street Fighter II Turbo comic.
- Gebsion - Attacked by Dark Sakura during the events of Super Street Fighter: New Generation.
- Adon - Defeated by Evil Ryu in the Street Fighter Alpha manga.
- Seth - Attacked by Akuma in the Street Fighter IV comic.
- Heihachi Mishima (Tekken 7) - Survived by sheer endurance and super strength, but was weakened as a result and due to it, was later killed by his son.
- While Kairi from the non-canon Street Fighter EX games is not a user of the Satsui no Hado, the power he wields works in a similar fashion.
- Fellow Street Fighter EX fighter Garuda is also said to be linked to said power in the EX games.
- In the iOS game Street Fighter IV Volt, the Satsui no Hado appears as a skill in Wandering Warrior. However, one would need the title "Messatsu!" to get this skill. When this skill activates, the player's avatar endures the hit that would have cost the avatar the match with 1 HP remaining, and then, it activates. While this skill is active, the damage the player's avatar scores on the opponent's avatar is increased
- In Capcom vs. SNK 2, Rugal Bernstein, after defeating Akuma, mixed the Satsui no Hado with his own Orochi powers and becomes God Rugal (sometimes referred to as Ultimate Rugal).
- Marvel Comics character Thanos is the first and only user who has obtained and used the Hado via artificial and mechanical means.
- In Marvel vs. Capcom: Infinite, Thanos claims that the Satsui no Hado has the power to destroy immortal beings such as gods, demons and even the embodiments of Death itself. This was foreshadowed in Akuma's win-quotes against Thor Odinson, Amaterasu and Shuma-Gorath in Ultimate Marvel vs. Capcom 3.
- In Sonic X, Sonic had gain a transforming that works in a manner very similar to the Satsui no Hado, this form is known as Dark Sonic.