Finally got off my ass and translated the whole thing. Reasonably accurate, I think, although I'm sure there will be nuances that I didn't pick up on.
The year is 1996.
Arrangements were already underway to hold The King of Fighters this year as well. However, unlike previous years, it was being sponsored by a massive conglomerate and thus being held on a major scale worldwide. The familiar faces of the nine teams remaining after the worldwide qualifying rounds lined up eagerly to face off in a test of skill.
However, among those nine teams were the names of the three people who had once attempted to seek world dominance. Could their objective be to crush the Garou team, and then the Kyokugenryuu team?!
And then, the one who showed up, teamed up with two mysterious women...when will his battle with Kyo Kusanagi take place?!
Even in the midst of this public King of Fighters tournament, dark clouds are already beginning to gather.
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In ancient times of legend, Susano'o defeated the Yamata no Orochi. However, the the true power of the Yamata no Orochi clan lay in Orochi's most powerful eight underlings, those who sought to plunge the world into darkness - the Hakkeshuu.
These eight individuals, said to possess the frightening power to crush boulders and tear through flesh, were feared as the eight heads of a massive serpent, or the Yamata no Orochi by the people of that era.
Even today, the descendents of this clan hide in the shadows and plot to cover the world in darkness. While it seems like there is a higher authority guiding their actions, that person's identity and ultimate goal are currently masked by a veil of secrecy.
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With the defeat of the Yamata no Orochi, the two schools of Kusanagi and Yasakani were established as the most powerful fighting styles in the world. However, Yasakani was drawn to Orochi's power and desired to possess it for himself. Thus it strayed from the path of good, and tried to reawaken the sealed Orochi's power. And once the monarch of the time found out about this, Yasakani was banished to live in seclusion.
At this time, no longer bound by the seal, one of the members of the Hakkeshuu killed Yasakani's wife as a sacrifice. Another member went to the banished Yasakani and told him thus: 'In order to atone for the sins of your clan, your wife met her death at Kusanagi's hand.'
Those words turned 1200 long years of trust between the two clans into hatred within an instant.
"You hate Kusanagi, don't you? Then join with us and use our power to exact your revenge."
And with that thought in mind, Yasakani formed a blood pact with Orochi in order to have his revenge on Kusanagi. From that day forward, he took the name 'Yagami' and created the most terrifying technique in history, the 'Eight Maidens' or 'Yaotome'.
Since that time, Kusanagi has fought to confine the nightmares unleashed at that time to the darkness, while Yagami broke its ties with Kusanagi and has instead fought for revenge.
This is the unknown sad history of those times 660 years ago.