How do you get a slave in the house in the elder scrolls oblivion?

First, you buy the Skingrad house Rosethorn Hall in Oblivion. It costs a lot (consider multiplying objects to sell to build up the money) and you need a lot of Fame, so cover this stuff first.

Second, buy all the furniture at the shop. Just follow the compass. You NEED to have the servant's quarters or Eyja won't move in.

Third, find Eyja. This isn't hard- she's usually at Colovian Trader's. Pay 150 gold and she's yours.