Aedra vs Daedra: what the difference really means in TES cosmology
People ask me this constantly, usually framed as "good gods vs evil gods," and that framing is wrong in almost every way that matters. The split isn't moral. It's a difference in what these beings did at the dawn of creation, and once you understand that, half the lore of the series reorganises itself in your head.
Start with the word. The simplest translation given in-universe is the one I keep coming back to: Aedra means "our ancestors," Daedra means "not our ancestors." Both groups are et'Ada, the "original spirits" who coalesced out of the interplay between Anu (stasis) and Padomay (change), or Anuiel and Sithis if you prefer the more abstract mythopoeic terms. So they start as the same kind of thing. The divide is about a choice, not a species.
The choice is Mundus. When Lorkhan (Shor, Shezarr, Sep, the Missing God by a dozen names) convinced or tricked a portion of the et'Ada into building the mortal plane, those spirits poured themselves into the work. And here's the part people gloss over: making Mundus cost them. The Aedra are the et'Ada who gave up most of their divine power to anchor creation. They bled themselves nearly mortal to do it. That's literally why the planets and the sun are described as their bodies or holes punched through Oblivion by their fleeing spirits. They spent themselves so thoroughly that what's left of them is barely present. The Daedra, by contrast, are the et'Ada who refused the deal. They kept their full power. That's why a Daedric Prince can manifest, scheme, grant artifacts, and run an entire plane of Oblivion as a personal kingdom, while the Aedra are silent and mostly absent. Strength isn't virtue here. The "weaker" gods are the ones who sacrificed.
So when a Nord prays to the Eight (Nine with Talos) and shudders at Daedra-worship, what he's really expressing is a kinship claim. The Aedra are ancestors, kin who suffered to make a place where mortals could exist and, crucially, where mortals can change. Grow, die, become more than they were. Mundus is the one part of reality with that property, and it exists because the Aedra mortgaged their godhood for it. The Daedra didn't give us anything. They're not our family. That's the whole emotional logic of the divide.
Now the question the brief wants me to land on, and it's a good one: were the Aedra heroes, or the bigger villains?
Push on it. Lorkhan's plan is regarded by some et'Ada as a betrayal so severe they tore out his heart for it. From the Altmer point of view, and the Thalmor build a whole ideology on this, Mundus is a prison. The Aedra didn't gift mortals a paradise; they trapped fragments of the divine in a place of death, limitation, and suffering, and then locked the door. The Altmer believe they're descended from the et'Ada and that mortality is a fall, a diminishment. By that reading the Aedra are the jailers, and the Daedra, for all their cruelty, at least never lied about what they are. Boethiah doesn't pretend to love you. Akatosh's deal, arguably, was the one that cost mortals everything.
I don't think there's a clean answer, and I think the series is deliberately built so there can't be. The Aedra gave us the only stage on which a Dragonborn or a Nerevarine can matter. Change requires limitation, and limitation requires the sacrifice that made Mundus. But they also condemned every mortal to that limitation without asking. Hero and villain aren't separable when the same act is both the gift of existence and the imposition of death.
For anyone who wants the primary sources, the Monomyth on UESP collects the conflicting creation accounts side by side ( https://en.uesp.net/wiki/Lore:The_Monomyth ), and reading them as competing propaganda rather than one true version is the right way in.
So here's what I keep chewing on: if the Aedra had refused Lorkhan's deal too, if Mundus had never been built and every et'Ada stayed a free, unspent god in Oblivion, would that have been mercy, or just an eternity where nothing ever mattered? Where do you actually land on Lorkhan: martyr, or the worst con artist in the universe?