Eric and Adelaide.
Well, they produced Willow. Eric is part fire elemental part Fury and Adelaide has Mist and earth healing powers.
They didn’t intend to have the “Chosen One” it all kind of worked out that way.
They tried to protect Willow growing up as she came into her powers early, hence their eventual decision that they must move to Texas in order to remain able to live a normal life without being discovered for their magic.