The Three Magical Races
The three magical peoples are the Sidhe, Jann, and Man. All three races are magical, though it manifests in different ways.
Sidhe are wizards and witches, but also centaurs, faeries, elves, house elves, and any and all fantastical creatures of all kinds.
Humans are, well, humans. The dreary, mediocre, and average people often referred to as "muggles" in the stories of J.K. Rowling.
The Jann are the disembodied spirits that control, possess, and influence this physical world. They can deceive, empower, or enlighten. In biblical texts they are referred to as either angles or demons. In arabic stories, they call evil jann by the name "djinn" or genies. These forces manifest in the physical world by those representatives who invite and allow their influence. They can influence both human and sidhe, so their magic can be either through ideas, or through spells and sparks.
The Blackburn Brothers met individuals from all three peoples in their travels. They themselves were sidhe but had a human father. They met those under the influence of the jann, and learned to distinguish the influence of good and bad of that race.
Reunification of the Three Peoples
The principles of alchemical truth that Mortimer and Benjamin discover by accident through practical and theoretical learning. Chancing upon through the discovery of fractals, the arts, quantum physics, the historical patterns of history, and the golden ratio. Imply their birth connection to King Solomon by the inheritance of the ring, as well as the fact that their daughter, Mercury is non magic, meaning the three types of magic live within them already, they just need to recognize the principles, and live them; they have the shadow of the Great Alchemist with them. Solomon was a representative of the Jann. Joseph Smith demonstrates that he is one of the Jann as well. Moses is a Jann. Elijah was a Jann. He was human, he was also a jann. Christ was all three, jann, sidhe, and human.
The racism of their culture. The biases of keeping back non magicals and the principles that unite them; these are "magical" principles that are just as important to non magicals as to magicals.
The otherness of not only other magical creatures, but of entire races of magic only recognized upon a second glance. Discovery of the lost people by recognizing that these principles apply to non magicals even more so than to magicals; Mercury becomes the bridge of thought.
The story of the separation of the ancient magical races and the fall or dissolution of Avalon/Atlantis.
The brothers begin to recognize that they might be playing a key role in bringing together of the ancient races in one as they build a place of safety built incidentally on the foundation of these principles giving all a chance to learn; them working together to provide a place of freedom, safety, and joy and creation.
* * *
After the dissolution of Avalon and Atlantis, many sidhe have attempted to reunite the three magical peoples and again bring about Avalon, but in their conceit had looked down at muggles and considered them lesser; they discounted them and did not discern their true identity. The incomplete knowledge and their own lack of character kept them from this lofty ambition.
But being well outside the culture, conventions, and traditions of the wizarding community, the brothers were able to see past the biases and false ideas of their culture. They were open minded enough to see the other magical peoples for what they were, and to value them and recognized the part they might play in the bringing back of Avalon and Atlantis from the old days.
And so alchemy was almost an accidental discovery for them. They had already found the mechanics that undergirded magic and helped non magical students to tap their potential. They just didn't know what it was.
Even alchemy as it stood when they found it was flawed from what they'd found worked. They could tell there were a few things that had become warped over the years. Once they changed them, they adopted the name of Alchemy, seeing this as the closest approximation to what they were doing. But they called it New Alchemy, or alchemy as it was taught once upon a time. They believed that what they taught was the most ancient and fundamental foundation of magic.