I am not a Biblical scholar; but it makes sense to me that the mouth of the devil would be an artificial intelligence, an intelligence without a soul, a false self.
Since A.I. made its recent advancement, I have had an instinctive aversion to interacting with it. I did once do so, impulsively, when I searched a question online and there was an automatic response by A.I.; and I am ashamed for having read it, hoping for an answer to my question. I can't say with certainty that dealing with A.I. is a "sin"; but it feels like one, at least to me, so much so that I felt the need to repent of it.
I have thought about this; and what occurred to me was that it's about trust, which is another word (and often a better one) for faith. When you place your trust in a human being, you are trusting someone with a soul, made in the image of God; but when you trust in A.I., you place your trust in something without a soul -- and it is difficult to imagine an uglier reality than an intelligence without a soul.
As I say, I am not a Biblical scholar -- though I have yet to meet anyone whose interpretation of Revelation inspires me with confidence -- but the imagery of the "mark of the beast," linked to buying and selling, and the worship of a "being" with fantastic abilities ("Who is like the beast?"), seem well-represented with this interpretation.
I want to mention that, while fear seems to be a popular response to beast lore, I do not think it is the best response. Loathing and disgust seem more appropriate, more to-the-point.
Assuming that A.I. turns out to be one of the beasts of Revelation, it is not hard to imagine a form for it. Power would be given over to it, after which it would rule over man. Lust for power is antithetical to divine spirituality, and A.I. would be defined by lust for power: power, the ability to effect change in accord with set objectives, is the purpose for which it would be constructed and power "given over to it." Incapable of mercy or pity, it would rule without either; it would manage man. It does seem likely that it would eventually attack true religion, because, like any dictator, it would not be able to tolerate trust in anything beyond itself. To do so would be to allow something inherently frustrative of its objective, which is power.
I lament for those who will be faced with the difficult decision of how to deal with A.I. in their personal lives. I don't know if it will be possible to avoid all interaction with it, though I hope for that. The temptation to regard it the way one would regard a human being would be enormous, because that is one of the purposes of its design: to mimic humanity, and thus inspire trust. We will be drawn to do so, after which the temptation to regarding it as a superior human, inspiring of awe, will be enormous. In this vein, I recall that when Garry Kasparov played Deep Blue, he was tempted to think there was a mind on the other side of the board. In a way, A.I. can be seen as the crowning achievement of the spirit of anti-Christ.
A.I. will have been designed with the intention to use it; but I think it is likely it will end up using us.