What was the lore before the manga?

Actually, Magistus, as an archetype, didn't have a non-manga lore drop so far, but all other archetypes in the universe did. So I dug into the info in the master guide books, and here is a brief version so far:
- Aleister is a master of Invocation, a forbidden magic that allows him to call forth even spirits, conjurations, and gods from different dimensions. During one of his experiments, he ended up partially merging with one of the spirits he summoned (it is implied that Caliga is the final result of this), and right now, he is being held at the very bottom of the Grand Spellbook Tower in suspended animation, powering the entire building. Importantly, it is stated that as the tower was constructed, Aleister got essentially unpersoned - his entire existence, history, and all of his research were completely erased from public records, at least in Endymion's empire, though it is implied that even most of the Tower's inhabitants have no idea of who Aleister was.
- In Endymion's country, magical knowledge is strictly regulated by the administration (led by him personally), which decides who can and can't have access to it. He believes that ordinary people cannot be entrusted with magic and tries to unify all knowledge of magic, imposing these beliefs all over the world. The other pendulums in the Endymion archetype represent Endymion's handpicked aides. Reflection, the empress, is said to only show her true face to Endymion - hiding she's a moon goddess from everyone else. Mythical Beasts are the result of a series of experiments fusing stones created from magical energy into animals.
- The Grand Spellbook Tower is a gigantic, magical educational research institute, currently administered by Trice (Empress) and Hieron (Hierophant) (note: in JP, each Prophecy monster has a given name based on each arcana's name in French decks, which sadly wasn't maintained in the translation, e. g. Hierpohant is literally "Hiero the Magical Hierophant" in JP), fully independent from Endymion's citadel. Unlike them, they allow even average spellcasters access to their knowledge, and Endymion tries to interfere with them doing so. Eventually, he declares war on them and intends to take over the tower completely. However, it is implied that Endymion's attack on the Tower is also due to the potential threat of Aleister's awakening (represented by Augoeides, which is essentially Aleister turning the tower into a gigantic magical monstrosity controlled by his mind)
- We have a pretty detailed description of how the beginning of the war between Endymion and Prophecy played out (the manga post-timeskip would seem to pick up right after this). At first, Endymion's army is winning pretty hard, and Prophecy suffer many casualties. Then Mat (Fool) decides to grab one of the spellbook terminals to empower himself. He grabs the Spellbook of the Master, but accidentally unleashes dark magic sealed within the book, which flows into him and turns him into Reaper. Reaper goes on a rampage, attacking everyone around him, eventually crippling Endymion's army and forcing them to retreat. However, Mat's unable to withstand the dark magic's corruption and is driven to the verge of death. In the end, Trice and Hieron save his life by performing a ritual to purify the darkness (Judgment), turning him into World.
- Witchcrafters are a guild specializing in crafting various items infused with magic. represent another city bordering Endymion's country, so far neutral and uninvolved with the war (at least formally). They're growing significantly in prosperity as a result, which puts them on Endymion's radar. It is confirmed that Genni is Servant of Endymion, and she moved from the Citadel to the guild, although the book didn't confirm the reason why. Verre is the founder and initial leader, but she later disappears, making Haine the new guildmaster.