Thanks of your precise statement ryyannon, unfortunately your source is not exact... suggestion to read the books of Pessoa without preconceived.
Satanism means adoration of the angel called Satan in the Bible, Pessoa has not even done never this in his masterpiece "FAUST."
But was interested above all to the occultism because loved Greece and ancient Italy where esoteric rites were practiced without prejudices.
Loved a lot the history and respect the religion reading well Pessoa was tied up deep to the sacred things.
So much legacy to the sacred to often converse with it and to reach to deny only to confirm later it importance some page... as can make a person in love that quarrels with the woman that loves.
Pessoa is a difficult poet because unlike the poets greengrocers communicated all the colors of his soul.
Sinned that who writes wise, comments or prefaces doesn't read more attentively that of which he speaks.
Many detaining on the poetry "the opium" have deduced that it was a hymn to the drug.
But few have thought to the historical period in which Pessoa lived.
If they had done they would have understood that "the opium" a medicine was considered to take care of the depression.
What anybody law of the epoch forbade the commerce and the assumption of the opium.
What a the artists' majority, misunderstood from own parents, were taken care of by the doctors for depression with "the opium".... and a lot of time later with the lobotomy.