Assassin

From The Elder Scrolls - Wiki on Neoseeker

Assassin is a playable class designed for Stealth characters.

Since the dawn of Tamriel their have been assassins. The people who kill others for money and reward. They are silent, deadly, and are experts at murder. They will use whatever tools they can to take out their target, but most assassins prefer the bow for long range hits and short blades for close-up work. Good assassins always get the job done no matter what the cost, and get their reward. Their is no doubt that the elegant art of the Assassin is profitable, for the art of the assassin will always be needed. Assassins are not always evil killers though, for their are noble assassins who only accept targets who are corrupt or evil. Their are many different guilds for these silent killers, secret or otherwise. Two of the most well known Guilds are the Dark Brotherhood and the Morag Tong Guild. Both Guilds have a deep hatred for each other as one is a lawful group of assassins while the other are ruthless killers. Be feared should you ever have a hit put out on your head for assassins are some of the most determined people in Tamriel, they will do anything to take you out as long as they get their promised reward afterwards.

Specialization: Stealth
Attributes: Intelligence, Speed
Skills: Acrobatics, Alchemy, Blade, Light Armor, Marksman, Security, Sneak

Possible Birthsigns

The best birthsigns for the Assassin class are The Thief and The Shadow for their obvious benefits for a stealth-based character.
Another birthsign that could be used is The Steed birthsign for its benefits to speed.

For more info on these Birthsigns and others see the Birthsign page.

In Morrowind

Assassins can make very profitable business in Morrowind. For one the Morag Tong Guild is staged out of Morrowind. Also their are a lot of factions in Morrowind opposed to each other, assassins are sometimes hired by a faction to kill a member of another rival faction. Morrowind In Game Description: Assassins are killers who rely on stealth and mobility to approach victims undetected. Execution is with ranged weapons or with short blades for close work. Assassins include ruthless murderers and principled agents of noble causes.

Specialization: Stealth
Favored Attributes: Speed, Intelligence
Major Skills: Sneak, Marksman, Light Armor, Short Blade, Acrobatics
Minor Skills: Security, Long Blade, Alchemy, Block, Athletics

Possible Birthsigns

The Shadow for its invisibility is a good choice, also The Thief for its ability to let you dodge enemy attacks.
The Lover for its agility boost and the paralyze effect.