I have started a new character for Skyrim, an Altmer. I am toying with the idea of a no armor, sword wielding and alteration mage. I guess my thinking is an elite Aldmeri operative...

What I am having issues with is how do I approach the various factions. The empire and Aldmeri don't really get along well, but better than the Stormcloaks. Strictly speaking, I think the Aldmeri would prefer that the empire remain in charge in Skyrim, if only because they would have to uphold the Concordant.

The Dark Brotherhood is tricky also, on the one hand, you could have a lot of chaos caused by killing both the emperor and the client, but does that fit with the Aldmeri agenda?

Ideas? I am really just looking for some ideas to flesh the character out.

Just be prepared to meet my sword.

...and I will cut you to pieces and feed you to my horse.

You might want to put a spoiler over the DB part...

Anyway, don't join the civil war. A continued war is more beneficial then either side winning.

Destroy the DB, the dominion has destroyed previous chapters already. You won't know the targets until you join anyway and there is no reason a Thalmor agent would join them.

A thalmor could justify joining either faction if you want to do those quests, after all having an agent that close to either the high king or provincial military governor would be almost as useful as the war itself. as for the DB the thalmor would likely destroy them as fishy said keeping with their previous trend.

While I agree, this would only really count if you already made a name for yourself in Skyirm, otherwise your chances of rising high in the ranks would be severly limited. Somebody that already leads guilds or has slain dragons or what not is of course going to be far more likely to rise then somebody who has not, and I still would not let my Thalmor character join unless it seemed likely that there would be a solution for the civil war.

Ah good point, i tend to save that one for last so i'm usually already head of all the factions and dragonborne ETC i hadn't considered a fresh character joining them

Be mole in Blades. You could impersonate dragonborn, gain trust with Blades and destroy them once and for all. But it would need some console magic to skip some parts of relevant quests.

A secret operative would have reason to do the part you are talking about anyway. Sometimes one brand of a government has to work against another to further fufill the overal goals a government has.

If it leads you the blades then all the better. The only problem is of course

Ignore the CW. The longer they fight between themselves, the less resources they can stockpile against the Dominion. Actually you could pretend your character was sent into Helgen to try stopping Ulfric execution in case Elenween (also there) couldn't convince Thullius that Ulfric should have been given into their custody. Thullius isn't naive and knows that the only ones benefitting from the CW are the Thalmor. He might have to follow orders but, behind his military compulsure and apparent indifference, he hates the Dominion with passion and he is looking forward to a revenge on the battlefield.

Go for the College guild. A Dominion agent is already there but it looks like he's a renegade and he stopped sending reports.
Then you could also infiltrate the thieves guild and take control of it. They've a vast underground network that could be exploited.

Actually thinking about it now, there is no way you could explain doing the college.

Oh I know how bout you get cut up and killed by every nord in sight Thalmor scum.

Looks like my horse will be well fed for a while.

Your Dragonborn living proof of Talo's divinity the Aldmeri Dominion would want you dead.

Maybe if I go former Aldmeri operative who is out to make trouble because of something on their agenda? That would make the majority of the quest lines acceptable.