I assume that's tongue in cheek. haha.
(though if it's not, that's pretty bad. No one should come with the house. Also, is your house upgraded, you know, when not glitching?)
Seriously? After defeating the dragon on the behest of the Jarl of Windhaven, he rewards you by making you a Thane of the city, with the right to purchase Breezehome, and a house carl, Lydia. A Thane is like being a city lord, and a house carl would be similar to being a knight/soldier in your employ. Once you have Breezehome, Lydia will live there... unless you loose her through a bug or she is killed in the game.
Lydia doesn't come with the house, but she is put into your service when you are made Thane.