Satsui no Hado

Name: Satsui no Hadou (殺意の波動, Satsui no Hadou, literally "Surge of Murderous Intent") (Also known as the Dark Hadou (ダーク ハドウ, Dakku Hadou, Dark Surge))

Known Victims: Goutetsu, Akuma, Ryu, Kairi (not truly the Satsui no Hadou but another type of power that is similar to it), Shun, Oni

Opposed by: Gouken, Ken, Ingrid, Rose, Ryu

Debut: Street Fighter Alpha

The Satsui no Hado' is a dark force and an evil murderous energy that Akuma uses to fight. Ryu was possessed by and had mistakenly awoken inside this energy inside of him to defeat Sagat in a drastic effort.

Description
To tap into Satsui no Hado, a fighter must be so consumed with the desire to win or have an intense rage that they are willing to actually kill. As a result, only people who push themselves to be the best at all costs can take full advantage of it. However, the untrained mind can be driven to a temporary insanity if they have not prepared for it. For those who do succeed in controlling it, they develop an almost cold, cynical detachment from themselves as well as others such as love ones and other people. As such, Satsui no Hadou makes a human unbelievably powerful, increasing their strength, power and speed beyond that of a usual superhuman fighter or a supernatural being, but at the cost of losing one's humanity and compassion.

Another side-effect of this power is that when a warrior embraces the Satsui no Hadou to their fullest extent, even when the warrior can not control it, they will develop a lust to fight to the death, their eyes will turn white or red, and their beliefs in fighting become very dark and cold-blooded. The warrior's personality will also change and become very violent and dark. However, as shown in the case of Goutetsu, if one embraces it to a small degree, their eyes pupils will become blue and have no willingness to destroy. Akuma may have tamed the Satsui no Hadou, but he could not stop the side effects of this unlimited power, although it is highly likely he had no desire to. His understanding of Satsui no Hadou is so great that he can seal himself off from it or embrace it to a lower degree, giving lesser opponents a fighting chance. However, he still can't turn back into his human self because of using it to his fullest extent for too long.

Ryu doesn't want to have the Satsui no Hadou inside of him or embrace it because he knows that he cannot control it and does not want to kill warriors that are worthy of murdering or warriors strong enough to fight him. Even if he learns how to control it, he would still lose his humanity like Akuma. Once a warrior has awoken the Satsui no Hadou within them, it can be very hard to resist it. Learning Satsui no Hadou is the first step in learning the most fatal technique known to all of their martial arts, Shun Goku Satsu if one has used it to their fullest extent for to long throughout years of their life, they will completely loose control and will transform into a demonic being that is similar to Oni.

Goutetsu
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 to a degree, which is why he kept his human facial appearance and did not demonstrate signs of any of the side effects. This was also how both his students Gouken and Akuma were introduced to the power. Goutetsu would also have had to teach Satsui no Hado to his pupils if he did teach them the Shun Goku Satsu, but Ryu (only in his evil state) can also use this move despite the fact that Gouken never did teach him the move, meaning that the move is an inherent quality of the dark power.

Akuma
After Akuma tamed the Satsui no Hadou, he lost all of his humanity, as well as his compassion as a person, to the point of becoming a fighter who lives only to fight and seeks worthy opponents that can match his power. In addition, he took on a demonic appearance to match his darkened soul.

Goutetsu was actually pleased and somewhat impressed with his student Akuma for tapping into Satsui no Hado during a life or death battle for control of their school - or so he thought. Akuma wanted to tap into Satsui no Hadou to become far more powerful, and wanted to use it for fighting to the death against warriors who he found worthy of killing, instead of using it for enlightenment and good. Goutetsu may have been unaware that his student had lost most of his humanity and compassion.

However, Gouken, a student of Goutetsu who taught a toned-down derivation of his style by removing the murderous intent, truly detested the Satsui no Hadou, since he believed it encouraged killing after seeing how Akuma used it to kill Goutetsu. He condemned his brother Akuma for corrupting his Chikara no Hadou (Surge of Power) and vowing to never teach it to anyone.

Ryu/Evil Ryu
Originally, Ryu scarred Sagat with a single Shoryuken. It was later retconned that Ryu lost control of himself and his rage by rising up fist first, scarring Sagat (and nearly killing him) 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 the Satsui no Hado, a great dark power that awoke inside of Ryu. During Street Fighter Alpha 2, Ryu finally realized that the Satsui no Hado was the culprit behind his cheap victory over Sagat. Knowing about this dark intent, Ryu has vowed to reject the Satsui no Hado. 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 of how long the seal will be able hold his Satsui no Hadou.