Why would an Altmer associate himself with people living in the sewers?

Information is always useful. Beggars are the eyes and ears of the streets. The Thalmor even have a contact who goes into the Ragged Flagon.

Not looking to good for an Altmer build then....

Well unless you insist on playing Thalmor the Altmer are just as viable as any other race. My main character is an Altmer barbarian.

Do you even own a PC?

I has me an http://imageshack.us/a/img191/2295/aa99.jpg currently. The extra +50 magicka helped early on, and the Highborn power enables fireball spam. Onehander skill took a bit of effort to get up to snuff early on, but this mage isn't squishy as is typical.

Go with the idea you are assigned to make changes to the thalmor in skyrim. Recruit faendal or khajiit. Kill ancano as he jeopardizes world safety. Complete assassins/thieves guild/mage college. Wear the robes or elven armor (there are no unenchanted thalmor robes?). I would side with evil whenever you can as they seem to be interested in power first. I wouldnt complete the civil war questline and would side with the dragon over delphine.

An honorable Thalmor is an oxymoron...that's like saying you want to create cold fire

I do not own a gaming PC. I play on PS3.

Nonononononono. No dark elves. Dark elves worship DAEDRA. No way the Thalmor and dunmer could ever be friends. Ask Brelyna when Ancano is still alive.
And what's wrong with jeopardizing world safety? It's not like the Thalmor want to save the world ...

To OP:

Making an Altmer is easy. Get a female Altmer pregnant. She will give birth to an Altmer baby. No matter what race the father is. Per ES lore.

Enjoy raising your Altmer child and schooling them in the most powerful magical arts!

Glad I could help.

P.S.
Don't ask me how to get one pregnant.
If in doubt, ask your mom or dad.

Was that one of your attempts at humour?

I was giving you the role-playing answer.

Made one myself just a while ago: http://steamcommunity.com/sharedfiles/filedetails/?id=175988369

Only she doesn't carry heavy weapons and armor around, she conjures them from Oblivion when the need arises

Any group has dissension within it. Even though your character is a Thalmor and agrees with their overall goals, it doesn't mean he has to agree with the way the current leadership is implementing those goals.

Play as a Thalmor dissident. He's at odds with the leadership, so they're trying to eliminate him. First, they send him to Skyrim to get him away from whatever power base he's been able to build in Alinor. Then, they betray his movements, causing him to be caught crossing the border and almost executed. When that doesn't work, Justiciars are told to kill him on sight. He joins the College of Winterhold in disguise to take down Ancano, a key asset of the leadership. He joins the Thieves Guild to make underground contacts. He avoids joining either side of the Civil War, as he doesn't want to end the conflict with a victory for either side. Without allies (he wasn't prepared for his exile), he's forced to work off-the-cuff, doing favors for some people to make them beholden to him, and for others because they have mutual enemies. He has to make quick judgements that may or may not come back to haunt him.

There's a lot of scope there to make alliances, look for dissident contacts, and join groups to cause misdirection and confusion. It might even be fun to have him act all arrogant and superior at first, but then quickly realize that won't get him anywhere and try (with varying degrees of success) to conceal his disdain for most of the people he deals with. Sounds like a pretty fun Chaotic Evil playthrough!

Oh, I remember now. About the Thalmor assassins. There is nobility in Alinor. You could just roleplay you either did something to aggravate one of the nobles there, or be someone of nobility yourself and other nobles trying to take you out.

I RP'd Mallariel (seen above) as a product of Thalmor eugenics with her father being from an old noble (pre-Thalmor) family, and who was secretly operating a sort of Underground Railroad for anti-Thalmor disidents and expatriates trapped in the Summerset Isles. She had some... "maverick" opinions garnered through her highborn education ("If we cannot go back like Auriel since we lost Crystal-Like-Law, why not go forward like Talos?") and frequently got into fistfights, and was once called a "little man-beast" by a particularly harsh headmaster because of her attitude.

She discovered her father operated a waystation on the underground railroad-like system when the Thalmor raided the place. Entrusted to a family retainer, she fled through that very network to mainland Tamriel and never saw her dear father again.

Only as she stared at the pile of bones that was once Mirmulnir, and that one guard said "By the gods, you're... Dragonborn!" did she suddenly realize why she never fit in while in Summerset: She was Dragonborn. Essentially, a Nord in a high elf body. Suddenly, it all made sense...

I have an rp Altmer who is a Thalmor Supreme being. He was sent by the Aldmeri Dominion to learn the nord ways if battle and to eliminate the weakling Ancano. His role is to join the companions and master their way of fighting - 2 hand, 1 hand and block while pretending to be a mage student at the school. One he masters the companions, he is to eliminate Ancano and kill every stormcloaks and imperial he sees.

Make sure your feet are nice and dirty so you can wipe them over your Legion soldier shaped rugs that seem to grunt every time you step on them.

I prefer my rugs made out of Stormcloak skins.