The MC Is a Male called Theo who is the reincarnation of a teenager who is a huge Ninjago Fan who got reincarnated in an Ninjago so he has knowledge about prior and later events of the show. In this storyline Theo is born around the same time as the FSM as a child from both the Oni and the Dragon but they are not considered related due to both coming into existence from similar situations, but not the exact same but regardless which way they are both of the Oni and Dragon with the same powers; in this AU The FSM and Theo have all Elements and Essences including secondary elements, Golden Power, as well as Energy Water, Darkness Wind, and Amber, etc; there are also changes to the Powers and lore in this AU seen below.
The Timeline may become mixed up at points with later events being foreshadowed in earlier sections of the story; Spinjitzu cannot only be retained for 15 seconds in this AU, it can be retained for any period of time depending on the skill level.
Amber was not an artificially made element in this AU, and both FSM and Theo can use it; it can also copy any element or essence in this AU but only if you have power equal to The Source Dragons, Theo, or FSM so Skylor cannot copy things such as Golden Power because she isn't as strong as them.
Elemental Dragons and Elemental Constructs still exist in this AU, the in-universe reason why they don't use this much MUCH later is due to the passage of time, though Lloyd, Theo, and FSM (though FSM being deceased by this time) can still use them. (Reasoning for Lloyd specifically will be given later in the story)
Both the Oni and Dragons (even hybrids of the two) can live to around 60,000 years old; in this AU the FSM didn't die due to old age, nor is he technically deceased in this AU, he simply moved his spirit to another realm, but he wont be returning; Despite the many mentions of the FSM he wont be an MC, more of a mentioned character who is just relevant for the main lore and an explanation of the rules of the powers in this Ninjago AU; despite having the same origin Theo and FSM have never interacted before.
In this AU the Oni have both Destruction and Darkness, it should also be noted that this storyline the Overlord is not an Oni but a spirit of their powers with their version of Destruction just being enhanced by the dark side of the balance itself; the Oni, Theo the FSM can use Darkness they simply choose not to, other than Theo himself who will use Darkness as casually as the other elements and essences in the story.
In this AU Source Dragons are the embodiment of the balance which they just choose to metaphysically manifest themselves as the Light Side of the balance (Dragons) which serve as the source of the Elemental Powers, Creation, and ordinary Magic, however they can also metaphysically become a Source Oni which serve as the source of Destruction, Darkness, and Dark Magic; though the Source Dragons will only appear as Source Dragons and not Source Oni in this AU.