Relationship between the Aedra and Daedra?

My first guess is that they pretty much hate each other.

And your first guess would be correct. To start off, According to Elder Scrolls lore, the term "Daedra" is of means "not our ancestors," as opposed to Aedra, which means "our ancestors."

Now, to further your question, you would do good to read this: http://www.uesp.net/wiki/Lore:Sithis
But here's the excerpt I'm interested in: "Sithis is described as an equal but opposing force to Anuiel."

And who is Anuiel? http://www.uesp.net/wiki/Lore:Anu
"Back before the existence of man or god, Anu the Everything created Anuiel—his soul and the soul of all things."

Now who are the Aedra? http://www.uesp.net/wiki/Lore:Aedra
"Aedra are original beings that arose from the interplay of Anu and Padomay." (Note: Interplay does not mean sex here...read on...)

But who is this Padomay? The answer to that, this link: http://www.uesp.net/wiki/Lore:Padomay , when combined with what you now already know about form the other sources, should give you a pretty good understanding of the relationship between Aedra and Daedra. On a side note though, it should be mentioned that the Aedra sacrificed some of their power to create our world, while the Daedra wanted nothing to do with that, retaining all power for themselves.

The only thing you have to remember is the Aedra actively participated in the creation of Nirn (using up the majority of their power in the process) while the Daedra did not want to have anything to do with the creation of Nirn and all life on it. The Daedra, for this reason, still retain all of their power. And that is why the Aedra are "our ancestors" and the Daedra are "not our ancestors".

As a side note, the Eight Divines are Aedra.

Aedra are Anu aligned et'ada and Daedra are Padomay aligned et'ada.

How much the Aedra actually created the world is questionable. Are they identical with the earthbones? Or did the Marukathi mantle them? (In that sense making them imposters)

yeah i might make a lenghty post if i see some discuss worthy point.

I don't know the difference between each. It's some of the doubts that I have about TES series...

Putting the Abrahamic concepts of Angels and Demons to the ideology behind the Aedra or Daedra is not absolutely correct. Though there's a line that makes both groups distinct from one another, it's incorrect to say that they 'hate' each other.

After the forming of Nirn, and the turning of many of the Aedra into aspects of Mundus- it's unlikely to see any communication between the Aedra and Daedra. Mortals would be the only ones to have a liking or disliking for the aforementioned primordial forces, as is evidenced by the Altmers' disdain for the Daedric princes. The Daedra themselves would regard their Anuic counterparts as being foolish for being tricked into sacrificing themselves for creation, and I doubt much else would be thought of them.

As for the Aedra, well they're dead. For the most part. What little sentience of theirs is left is most probably fragmented and trapped.

Well, the Eight would be "dead", as you say, but Magnus and some other Aedra escaped. I think the Elven gods (Auri-El, Magnus, etc.) are still "alive". Didn't all of them flee to Aetherius? or was that just Magnus and some of the lesser Aedra?

TES lore is too confusing.

here is the thing.
The distinction between the earth bones (those aedra that formed Nirn) and the the magne ge is somewhat muddy.
See. most gods have an oversoul.
And this oversoul has various aspects.

Lets take for example the oversoul of the name Aka-tusk.
Aka-tusks aspects are Akatosh, the time dragon, the eater of worlds alduin, his firstborn son who COULD also be Satakal (but satakal could also be lorkahn) and also Auriel. None of these aspects have much in common.
in fact. Auriel fulfills the same role as Magnus. who fled creation. You see. Its a bit muddy.

The prime distinction between Aedra and Daedra is that the Aedra are sub gradients of Anu, while the Daedra are subgradients of Padhome.
Well. thats how it used to be anyway. However then we got Trinimac and the Champion of Cyrodiil that kinda mess that up. Still padhome ALIGNED tho.

the Daedra cannot create. Thats the biggest thing. This is not because they did not take part in creating the world.
This theory is supported by the fact that Lorkahn could not create either. Beeing the son of Padomay.
Padomay is change without creation, while Anu is creation without change.
Only where they overlap creation can exist (MUNDEX ARENA)
In other words the Daedra cannot create, but only pervert.

The whole "Angles / Devils" thing is complete bs. I know Todd Howard said that once. But everything he says is BS.
Its more of a "general Apathy" on the Aedra and "boredom" on the Daedra.
They are not good or evil. The definition "blue and orange morality" that TV tropes made up fits perfectly.
Of coruse there are some Daedra like Azura that is considered less malevolent than lets say Mehrunes dagon. But thats just because of the Personality of said prince.
In some ways. Azura too is just a vengefull bitch who created the Cult of the Nerevarine to get her petty revenge on the Tribunal.

Ah, Magnus. Yes, he fled to Aetherius with some lesser Aedra, but Auri-El did not. Refer to the Aldmeri creation myths. Auri-el was present when Lorkhan's heart was shot over to north-western Tamriel; after creation. Thus, like the other Aedra, he became part of the Mundus.

As for whether the Aedra are alive is debatable. We see avatars of Lorkhan, the Shezzarines, as manifestations of the trickster god's essence. And Lorkhan is also in the form of Shor in Sovengarde, and Talos also appears in the form of 'Wulf' in Morrowind.

There are most certainly parts of the Aedra's awareness out there, but for it to manifest is rare.