Chapter 1: Legend of the Four Oni's
Once upon a time, when the First Ninja of Norrisville was still active, the Sorcerer wanted something that would catch the Ninja off-guard, basic Stanked townspeople was never a challenge for the Ninja, because of this, the Sorcerer came up a horrific and brutal idea that will most likely succeed in the killing of the Ninja and the destruction of Humanity.
He stanked various townspeople but instead of making them cause havoc and destruction, he instead using orange stank instructed them to capture many various animals, when the Sorcerer was given many animals of various species, he filled them with the green mists and streams of pure corruption. This is how the Oni were born.
The Oni are corrupted animals due to overexposure to the Sorcerers magic, the Oni were brutal and sentient soldiers to the Sorcerer, more looking like bipedal demons, gargoyles, orcs and trolls rather than actual animals besides maybe bearing fur or fangs, the fangs and hooves being mementos to what they once were, they do not require the orange stank to be controlled by the Sorcerer for they were intelligent enough to understand commands, they love to inflict harm, love to kill, and most importantly, it takes a lot of effort to kill an Oni, for once they sustain fatal injury, they can possess objects so they can find an opportunity to possess passing by animals so they can resume their quest to spread more havoc, the only way to kill an Oni is to destroy the object they possessed before they possess another animal or in some cases if they want a weaker body, a human.
While the Ninja had to deal with these marauders that lusted for destruction, he wasn't alone, due to Oni's being sentient and intelligent (to a fault.), they were able to learn more about humanity, due to this exposure to humanity and how it can calm the wrath of a violent Oni and make them think more independently about themselves, some Oni believed that the Sorcerer's plan of pointless destruction was moronic at best believing that his plans lacked focus, lacked logic and lacked security for the future, because of this realization their lived four Oni's of four different colors that helped the Ninja for they shared a common goal, protecting the mundane townsfolk from their own kind who refuse to disobey the Sorcerer despite being able to do so willingly, the Yellow Oni was honorable, strong, disciplined, morally just and a master with an axe, the Red Oni was hotblooded, violent, aggressive and loud but was a master of the sword and enjoyed fighting his own kind, the Blue Oni was a master manipulator, was extremely cunning, dangerously arrogant and surprisingly skilled with a trident, but he viewed humanity as a merit and thus helped out of the Ninja, and finally, the Purple Oni was carefree, innocent, childish, and upbeat but was a master with the bow, he only helped the Ninja because of the fact that his friends were helping him too.
With the help from the Four Oni's, the Oni were defeated, due to these failures, the Sorcerer never created Oni's ever again, when the ashes settled, the Ninja was faced with a problem, even though they were his allies, the Four Oni's were still Oni to begin with, the First Ninja wanted to make the Sorcerer know that making and creating Oni will never work against the Ninja, so with some reluctance, the First Ninja slew his allies, the Four Oni screamed in betrayal and agony as they possessed their weapons like any Oni would do if they wanted to live once more after taking a fatal blow. The First Ninja collected the weapons of the four Oni's and as an attempt to apologize to the allies that he betrayed, he placed each weapon in different areas of the outskirts of Norrisville, he placed the Yellow Oni's axe deep in a cave where the silence of the cavern is only interrupted with drops of water, he placed the sword of the Red Oni in a place where heat and survival is prominent, he placed the Blue Oni's spear deep underwater of a lake where no human thinks of due to the danger it harbors, and the bow of the Purple Oni was planted on top of the highest point of Norrisville, all away from mundane humanity. Giving them a quiet and somewhat tranquil rest that they deserve after serving the Ninja and then being betrayed by him.
Of course, this was a long time ago, things change, Norrisville changes, social norms change, the Ninja and the Sorcerer Changes, ideals change, and even the location of the Four Oni's weapons change as well, but in this story, we aren't focusing on the Ninja of Norrisville (well, not focusing a lot on the ninja.) we're focusing on someone else, someone completely different.