The ultimate goal of the Ethereals in subjugating the Human race, the Avatar is a Human/Ethereal hybrid. As XCOM discovers, the Ethereals' entire species are dying out as their frail, atrophied bodies have become unable to sustain their major psionic power. To combat this, they have invaded and enslaved other species, including the Sectoids and Mutons, in order to use them to create new bodies capable of sustaining them. As evident in the mere existence of the Avatar, the Human race was proven to be the compatible species for this plan.
