Plot Point 1: Lotus awakens the sleeping Tenno after millenia.
- not all Tenno can answer or are available. Some died during the Long Night, and others were taken by Corpus, Grineer, and even Infested troops before they awoke.
- heavily implied that all Tenno went to cryosleep at about the same time, though certainly not all in the same place.
Plot Point 2: While Grineer and Corpus do trade with one another, they are not allies.
- there are mentions of diplomats and such between the two, but their objectives mainly seem to treat diplomacy as another front of war. Assassinations of diplomats are mentioned in-game (regarding Counselor Vay Hek, and more recently, Alad V. on the Corpus side).
Plot Point 3: Lotus being somehow formerly affiliated with the Corpus.
- It is never mentioned how, or in what way Lotus was affiliated; this is inferred from Corpus named characters referring to the Tenno as the Betrayers, with Lotus as The Betrayer.
- Little else is known about the Lotus herself, other than she runs mission control for Tenno. She might be an actual living being, or an advanced AI - in either case though, she uses a human-like avatar to speak with others.
Plot Point 3: The Infested don't really have diplomats.
- The closest they get to diplomacy is when the Golem, or Phorid talks to you during their Assassination missions, expressing confusion as to why "you're killing your own flesh." This is a reference to the Technocyte virus that altered the Tenno from baseline human in a controlled fashion to that which could use the Warframes, versus the uncontrolled and "wild" version that gave rise to the Infested. The Infested aren't able to understand, or simply don't care about the distinction.
Plot Point 4: The old Orokin Towers don't like anyone.
- former Grineer, Corpus, and Infested troops are all seen within the Towers with that gold-hooped thing attached to their faces (or in the case of the Ancients, whatever passes for a face in their case). They no longer sound or act like themselves, and all work together in a coordinated fashion to repel any invaders, including Tenno.
- The Orokin Towers themselves are hidden within the Void, accessible only with Void Keys. Some of them have been untouched by the ravages of time, and others have become derelicts due to the Infested discovering them.
Plot Point 5: While the Grineer and Corpus have powerbases within the Sol System, the Infested have used the Void as their powerbase.
- with Alad V. pretty much booting the old Golem out of Jupiter, the only place left as a powerbase inside the Sol System for the Infested is Eris, where Phorid still hangs out.
- on the other hand, all the "derelict" Orokin Towers appear to be overrun with Infested, and one of those is where the huge Infested entity Lephantis makes its lair.
Plot Point 6: The newly-reawakened Tenno only have themselves, and abandoned Clan Dojos to their names.
- the Clan Dojo game mechanic is analgous to a reawakened Tenno finding one of them and unlocking it, and then using it as their home base. The game is very unclear as to how many of those there are, as it strongly suggests a more local mindset in which you and your Clan are some of the few who managed to band together and use an old Dojo as a home base.
- However, the Tenno still have no fleets, troops (other than themselves) or anything else to their names, resulting in the game mechanic of sneaking into Corpus/Grineer/Infested ships/outposts, and causing trouble of various sorts for fun & profit.
Plot Point 7: The Stalker thinks that though the Tenno don't remember what happened before the Long Night, not remembering is no excuse.
- there's this nice writeup in the Codex after you manage to scan the Stalker three times (heh, have fun with that given his current loadout), that goes as follows:
- so, apparently Tenno were responsible for ending the Orokin Empire right after a war in which the Tenno were instrumental to winning, if the Stalker is to be at least partially believed. If he is telling the truth, then he's a very old soldier; not a true Tenno, but a Guardian with similar capabilities to a Tenno, if not the same social status."Some have walked these desolate worlds while you have slept. Some like me. I remember what you did. I remember the day.
The Tenno appeared at the Terminus, gleaming and victorious. Our cold and gold Emperors, breathless, bathed you in savior's silk. Then came the sound. Across all our worlds, all at once, the ceremonial Naga drums. A royal salute to the honored Tenno. Ten solemn beats to declare the suffering was over. I watched from a distance, with the rest of the low Guardians. With each beat terror began to crush my throat. The Tenno were not stoic and silent. They were waiting. They were poised. I tried to call out but only a strangled whisper escaped.
When the ninth beat rang a torrent of blood filled the stadium, loosed by Tenno blades. The drums, the Empire, fell silent forever.
Now I hunt, dividing your numbers. Watching from that dark place, cataloging your sins, I am the ghost of retribution. You may forget but you are not innocent."
- It's an open question as to the Stalker's motivations, as the Tenno are just now waking up, with the Corpus, Grineer, and Infested running wild through the Sol system for quite a while before this. Whether it's an absolutist "Oh, showing your faces again? No matter what, I gotta put ya'll back to sleep, for good this time", or something more nuanced is unknown.
- It is at least shown that in-game, the Grineer, Corpus, and Infested will all attack the Stalker on sight if he appears, so he doesn't appear to be allied with any of them.
Plot Point 8: The Orokin, and the Long Night are things that happened "back there."
- It is unknown exactly who or what the Orokin are, except that they were at least partially synthetic in nature, and were responsible for the formation of the Tenno during the Orokin Empire. The Orokin used the Technocyte virus (the same that created the Infested) in a controlled manner on unmodified human beings to alter them enough so that they could bond with the Warframe suits, and use them essentially as a second skin.
- The Long Night is what the Tenno & the Lotus refer to the time that they were sleeping. During that time, the Orokin Empire fell, and the Grineer and Corpus factions arose out of a cloned army expanding and consolidating power (the Grineer), or the scientists and economists trying to create their version of an aristocracy (the Corpus). The Infested presumably managed to break loose from one of their containment cells, and escape into the solar system at large to begin om-nom-nom'ing.
Plot Point 9: The Technocyte Virus
- named as responsible for making the O.G. Tenno (Hayden Tenno, from the game Dark Sector) in a primal way, due to Hayden's sheer force of will (and random drugs)
- responsible for turning a normal human into a Tenno with enhanced physical attributes, capable of wearing and using the biomechanical Warframes
- also responsible for the Infested, which is described as an "uncontrolled strain" of the Technocyte virus
Plot Point 10: Tenno Don't Remember Shit
- either due to how they were awakened, or how long they've been asleep, a typical Tenno has severe memory loss, though retain their skills with guns and melee weapons
- whether this is by accident or design is unexplained
Unexplained Plot Points:
- The Solar Rail network. This is a high-speed travel network implied to connect all planets and major moons of the Sol system, control of which currently belongs to the Corpus. Since the Tenno have no real ships except their small infiltration shuttles, they must use the Solar Rail network to travel to various places within the solar system.
- Heavy terraforming & rearrangement of planetary entities went on in the past. This is shown by Phobos being a proper moon with an atmosphere, as opposed to the asteroid it is today, Europa being its own planet, and several other little touches. Other touches are the Void Keys, which trigger space to "bend", allowing ease of travel into specific locations within the Void.
- The Void is not explained. All that is shown is that anytime you're able to see into the Void itself (either when leaving a Tower, or through some of the windows), it looks... not at all normal for how space looks. It is also said in-game that the locations within the Void are not visible from "normal space," and that one must have a corresponding Void Key to access a given Void location.
- No real endgame envisioned. The Tenno wake up, wreak havoc on various Corpus/Grineer/Infested ships or bases, and then... profit? Other than exploring stuff, there is no real goal set in mind for the Tenno, whether of their own choosing, or at the Lotus' suggestion.
(edited with suggestions from Frogid, regarding the Orokin, the Orokin Towers, the Long Night, and the Grineer/Corpus/Infested factions.)