A concerning issue about the apparition of Fatima that does point to a demonic intervention is the last apparition when the "Miracle of the Sun" happened. There was also another less commented apparition on that day, that had been announced on September 13th, 1917.
Our Lady would have asked them to pray more with the rosary and to use the self-flogging whip only during the day(!!!) and said, in Portuguese:
"Em Outubro, virá também Nosso Senhor, Nossa Senhora das Dores e do Carmo, São José com o Menino Jesus, para abençoarem o Mundo."
"In October, Our Lord, Our Lady of Pains, Our Lady of Mount Carmel and Saint Joseph with the Boy Jesus will come to bless the world".
And indeed, on the day of the "Miracle of the Sun" these "beings" were also seen.
Now, here is the concern. First, the support of self-flogging. That's always been a controversial practice at best in the RC church, and, to my knowledge, never approved in the Orthodox church. Second, and most importantly, the apparition of the "Ladies". It's always been understood that the Holy Virgin's titles are only that: titles. Even when she appears dressed as in an icon, she comes humbly and majestically as "just" the Mother of God. The apparition of such "characters", which were first "Our Lady of the Rosary", then "Our Lady of the Pains" and last "Our Lady of Mount Carmel" spells too much of a female trinity, which would be a typically quasi-pagan demonic mockery. Plus, all the atmospheric "miracles" resemble too much the phenomena mentioned in the book of Revelation as demonic signs to deceive "even the just".
I'm not saying that it *is* a demonic phenomena. But it sure looks like it.
Perhaps there was symbolism in why she appeared under those specific titles? http://unveilingtheapocalypse.blogspot.ca/2012/08/our-lady-of-mt-carmel-visions-of-fatima.html