Hi! I have three Elden Ring lore questions, both of them are kind of big, so you can focus on one or the other if it pleases you.
So first, I still get somewhat confused on the connection between the erdtree and the greater will? Like, the erdtree (in its primordial form the crucible) seems to be the genesis of all life on whatever planet the lands between are on, but the elden beast seems to be extraterrestrial in origin? Is the erdtree an alien being, or has it merely been parasitized by something cosmic?
Second, the details around Marika's ascension to godhood and subsequent crusade seem hazy to me. We know she hails from the shaman village in the lands of shadow, and that after she ascended to godhood she sent Messmer on a crusade against the horned ones because of what they did to her people, but when did the crusade begin? Sometime after she became the vassal of the greater will, and before the night of black knives, but can we narrow down the time frame further?
Finally, what the hell is the Scadutree? A minor erdtree planted by Messmer's crusade as a symbol of the erdtree's dominance over the crucible? What caused it to become tainted and thorny?
Thanks, Lore Mom
OK HERE WE ARE! @morgcorr sorry for the wait. i'll try to keep my answers relatively brief for the sake of convenience.
The Crucible is NOT the primordial form of the Erdtree. The Erdtree was specifically a symbol of the Golden Order, Marika's regime while she was the god of the lands between (TLB.) She was not the first god or leader of a regime; Placidusax was at one point the Elden Lord of a different god who ruled over a dragon-led society from Farum Azula, for example. So the Erdtree was grown with Marika's power and isn't necessarily alien in itself, but the Elden Beast IS alien, as is the Greater Will. This was already my main theory but the DLC confirmed it as well with Metyr's lore. Basically the Greater Will was an all-powerful cosmic entity of some type that created life and such and upon doing so sent down some of its creations/children to guide new life, such as by having Metyr run the fingers and have the Elden Beast watch over the Elden Ring.
The crusade definitely took place after she ascended to godhood and before the Night of Black Knives because that was followed pretty swiftly afterward by her smashing the Ring. As for where it fits in the timeline, the general consensus is that Messmer is Marika's eldest son and that it took place before any of the other stuff we see post-godhood. However, I differ from my colleagues in that I believe the crusade actually took place LATER in her reign, perhaps near the end of it, and that Messmer was not her eldest child, but that's a much larger discussion.
The Scadutree is quite literally the shadow of the Erdtree (roll credits ding!!!!) but hidden away through the magic power of the Sealing Tree, the Suppressing Pillar, and Marika's manipulation of the Gate of Divinity. The Erdtree doesn't cast a shadow because Marika hid it from view, and in doing so hid away all the lands touched by said shadow. The tainted thorniness represents Order's decay and also possibly the twining of Godwyn's thorny roots. I have a lot more to say about this one but it's still percolating in the theory laboratory so I'll get to it later.
I hope this helps! Thank you for asking!
-Lore Mom