In lien theory states, the borrower (also known as the mortgagor) keeps the title to the house, but the lender attaches a lien to the property. The lien gives them the right to seize the property if you fail to meet the terms of the mortgage.
If you buy a home in a lien theory state, you hold on to the title as long as you continue making your payments and abide by the terms of your mortgage.