Back to the source, Orchid and Morningrise.
To me, the spirit of Opeth reside in the two first albums (Some parts of My Arms Your hearse too).
Something bordering on a "The Twilight Is My Robe", in the connection with the touch of a "Requiem" with the enthusiasm of an "The Apostle In Triumph", the alchemical plurality of a "Black Rose Immortal".
I request the essence.