RWBY: Oscar's slice of the multiverse

Hear me out on this fanfic idea

In my AU, the Curse of Almet, the Lemon Boy is a fairytale about a young farmhand who goes on a quest, donning a straw-hat and armed with an axe and a silver shield ornate with rubies that passed down in his family, to vanquish an evil conqueror wizard whose army had ransacked his village.
On his way the Lemon Boy encounters a widowed woman who tells him of four knights who had lost things of theirs to the wizard, and who will help him if he gets them those things back.
The Boy goes out to search for the knights and finds the first one, from whom the wizard had taken his wisdom. The Boy removes his hat and remakes it into a brain which he gives to the knight.
The next knight had lost his heart, so the boy forges him a new one out of the steel of his axe.
From the third knight the wizard had taken his feet. The boy sacrifices his shield of silver and rubies and forges it into a pair of feet for him.
The last knight lost his courage, and that is hard to restore. Lemon Boy and the other Knights talk to him for days until he gains courage and joins them.
The end of the story is expected: the Boy and the Knights reach the Wizard's Emerald Tower, fight their way through Grimm and Men to the top, and finally slay the Wizard.

The Wizard is non other than Ozma, whose soul the God of Darkness had infected with Grimm essence, corrupting his heroic nature. In this world he is a conqueror and a tyrant. And though in the present he had taken to lead his campaigns by corrupting mortal societies and uses the Grimm less and less, in myths and folklore he remains the Lord of the Grimm.

The widow who sent the farmhand to seek out the knights is Salem, the Goddess of Recreation. After the Brothers destroyed Mankind and abandoned Remnant, she traveled the world and studied nature, discovering evolution. And through hundreds of years of selective breeding and magical manipulation she had remade Man. Unlike in the show, Salem and Ozma are at a sort of peace with each other. Neither of them wants the Brothers to return and they both work to keep the Relics separated so that it does not happen. However, they do send their followers to sabotage each other's efforts when they think the other is overstepping. Salem is the one who wrote the Lemon Boy.

Speaking of which, the heroic farmhand in reality is a hulking, savage, man-eating mutant. Where did he come from, no one knows. But wherever Ozma is he goes, hunting him, for hate of Ozpin fills and fuels him. He is a shapeshifter who can turn humans, faunus and animals into undead hordes. He first killed Ozma in Vacuo that he had conquered, and its people called him Almet, undead in their tongue. And undead he is, always returning from death no matter how gruesome and terrible. Each time that he returns to life he finds four men and makes them into his Knights of the Four Winds, his agents in each land who disturb Ozma's influence and weaken his grip on them. If Almet dies they die too, but so long as he is alive they can never be killed. The knights possess all the aura and semblances of their formers, as does Almet, and they can also copy those from others by consuming their flesh, which is also how they can create undead hordes. It is because of the Knights that Ozma created the Grimm Maidens, who are also responsible for ruling the Four Kingdoms between his lives.

The Maidens are still named after seasons, but they have much less magic, and instead their powers are mostly Grimm-based. Since they were created to combat the Knights of the For Winds, the Maidens are similar to them in abilities. They can steal aura, but not semblances; they can infect people with Grimm essence that lets them control them. The Maidens can also command Grimm. They have limited magic, a fifth of Ozma's magic divided among them. That is enough to form weapons and generate small attacks like a fireball or a lightning bolt. Ozma can usurp control over Grimm and Grimm-infected creatures from the Maidens, and he has a level of control over the Maidens' bodies and minds which he uses to put them in their place if they act out of line. Ozma can also take away a Maiden's powers by killing her, and he can force the power into another female.

In the Great War Salem formed an alliance with Almet to liberate the Kingdom of Mantle from Ozma, but when she saw the devastation that Almet's forces delivered as he made for Ozpin she turned against him, and together with Ozma imprisoned him in ice. Salem agreed to let Ozma continue to rule Mantle in order to ensure that Almet stays imprisoned.

After the War ended Nicholas Schnee created the SDC. Ozma, then the Chancellor of Mantle, approached him and offered to support his company if he helped him keep Almet imprisoned. After Atlas was raised into the sky and the kingdom was renamed for it, Nicholas built a dungeon under his manor that Ozma transferred the ice-chunk containing Almet into. There he was kept for 50 years, a trophy of sorts in the wealthiest house in Atlas. Ozma kept a close relationship with the Schnee Family, even becoming romantically involved with Willow and helping her keep Jacques from taking over the house, effectively making him into a puppet CEO of the SDC. He acted as a father figure for Winter, Weiss and Whitley too.

All of this angers Jacques and he begins to probe around to try and take Ozpin down, inevitably discovering his true identity and history, as well as who are the people who work for him. Terrified, he eventually makes the decision to release Almet. Ironwood and Winter, who already know Ozpin's secrets and serve him, attack him in the dungeon and manage to kill him in front of Willow, Klein and Whitley who followed them there, but not before Jacques blows up the ice, freeing Almet. Almet immediately kills Ironwood and Winter. He catches Ozpin's smell on Willow and proceeds to eat her alive while Whitley watches. Then he mutilates Klein and leaves. He ravages Atlas until he finds Ozpin, battles him and kills him.

Ozpin reincarnates into Oscar and kills his aunt, forcing him to leave his home. They go to Mistral to tell Senator Lionheart and Blake, the Spring Maiden, to ready the army and the huntsmen, but discover the hard way that Ozpin's allies had been planning to usurp him for years, and that Almet only made it easier for them to take over his secret empire. Ozpin retreats into Oscar's subconscious. Oscar barely escapes Blake and hides in the slums of Mistral, where he is found by Raven who does not ask too many questions and helps the child she found escape Mistral and get to Vale, where Salem lives and serves as a councilwoman.

Oscar is brought to the mansion of Roman Torchwick, who in this world is a movie director and Neo is his effects expert. Oscar stays with them for some weeks in which he keeps secret the reason for which he was persecuted. Eventually Salem is called over to take him somewhere safer, because Glynda, Qrow and Ruby the Fall Maiden are quickly taking over Vale. However, once Salem sees Oscar she immediately attacks him for seemingly no reason, forcing Ozpin to come out and tell her what happened. Though some of Salem's allies protest, Oscar is delivered to Glynda who has Team JNPR guard him, as Ren's semblance in this world is the power to suppress aura which he uses to keep Ozpin at bay.

In that time Oscar meets Ruby. As a child Ruby witnessed her parents being murdered by Qrow, who then kidnapped her and Yang and brought them to Ozpin, who forced them to become the Summer and Fall Maidens. Obviously she hates Ozpin and all his treacherous followers and especially Qrow, but she always tells Oscar that she does not see him as Ozpin and that they are in this together. This is all manipulation, however. Ruby plans to use Oscar to get more useful information about Ozpin, and possibly steal his magic. Oscar falls for her and follows her around for the time being.

Meanwhile, Almet reaches Mistral where he finds a rebellion led by the allied forces of Adam Taurus' White Fang, the Branwen Tribe led by Raven, and civilian militias led by Huntsmen and soldiers who deserted Mistral's ranks. He takes an interest in Team SSSN, eventually convincing them to become his Knights. The Four split: Neptune takes to the sea to clear out the Grimm infestation that Blake created to keep Mistral isolated, Scarlet uses his mutated flesh to turn a shipwreck into a flying base for the horde of zombies and Huntsmen he takes to Atlas, Sage and Sun go to Sanus where Sage stays in Vale while Sun continues to Vacuo.

To be continued...