My original question was this
I purchased a house on land contract --- The warranty deed is in one persons name and he quit claimed the house to his girlfriend. She is the one who I have the land contract with. Is it legal? And can he take the house back?

What I did not include was ---

Raymond - purchased the house and financed it through a bank. There is still a balance owed to the bank. He then Quit Claimed it to Diane (girlfriend). She then signed a land contract with me --- Does this change you anser?

As long as Diane had the deed recorded, she owns the property and has the right to sell it. But the property is subject to the lien of the mortgage that Raymond obtained when he financed. That mortgage has to be paid in full when you get the deed or you won't have clear title.

But I will say that it is not uncommom for property being sold on a land contract to have a mortgage against it, I do it myself. I use the payment I receive from the person with the contract to pay my mortgage. The idea is that your payment pays for the house, and since you are paying more and longer, it will be clear before it is time to sign a title over to you