Ray was a keyboard wizard. The Doors didn't have a bass player, so Manzarek played all the bass parts, as well as the melody, rhythm, etc.
Ray and Jim Morrison had a bond that allowed Ray to compose and play Morrison's poetry and emotional shadings in terms the rest of us could understand. Everyone has heard "Light my Fire", but "The End" is as haunting a lyric as has ever been written and sung - pure brilliance.
God bless them both - I'm certain they are in the Morrison Hotel sharing memories and spirits together again.