Alyx was raised by Eli in the world controlled by the Combine, likely at Black Mesa East much of the time. During this time, Alyx was also on good terms with Isaac Kleiner, referring to him as "Uncle Kleiner" in an affectionate portrait she once offered him. During Alyx's childhood, Eli used scrap metal to create Dog, a sentient robot designed to protect her, making him physically powerful, intelligent and with an in-built sixth sense so that he could always know Alyx's whereabouts. Although the initial model was a mere meter high, Alyx added new parts to Dog over time, making him a towering 2.5 meters high at the time of Half-Life 2.