Satsui no Hadou

Satsui No Hado (殺意の波動 Satsui no Hadō, lit. "Surge of Murderous Intent"),

The Satsui no Hado is a form of ki that is rooted in the darker aspects of a sentient being's 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. The Satsui no Hado is the other half of the Yin Yang dual philosophy that is deeply ingrained in the culture of Amaterasu.

To tap into the Satsui no Hado, a sentient being 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 瞬獄殺, Shun Goku Satsu, lit. "Blinking Prison Killer" ), 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 and avenge.

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 story, Tama Tenkai 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, usually there will be a visible leak of Ether, in a form of dark aura. If one embraces it to a lesser degree, not much physiological change seems to be present lest a blue glowing eyes. If one balances the Satsui no Hado and the Mudou Ken , 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 an immortal parasitic demonic entity, likely one similar in appearance and personality to an Oni/Demon/Iblis/Rakshasha of legend.