Once again, I will try to be brief, even though it’s not possible. 🤪 As far as demons lying, I couldn’t give you a definitive answer.
Let me say this. My wife and mother in law, were from Batangas. My MIL always used to say, you better watch out, or you will get pinched by a dwarf. I just assumed it was typical superstition. One day, the two were watching TFC. I wasn’t really paying attention, since I don’t speak their language anyway. At the end, in perfect English, they always answered questions people might have. Once, they said, what does it mean to be pinched by a dwarf? That brought me to instant attention. I don’t remember what they said, but they had video of it. I figured it out, in about 3 seconds. These were not dwarfs. They were little children, and were demon possessed. You could see it in their faces. It was grotesque, and ugly, with a capital U. I don’t know if all demon possessed people act like these children did, but some surely do.
It seems to me, that demonic activity, like this, is somewhat common in the remote mountainous areas. I have been there, and sometimes (not always) I felt like there was an oppressive presence, close by. I honestly felt like I was in the presence of evil.
I think I know what you mean by sensing an oppressive presence. Whether imagined or real, I have always had such a sense when in some places (in certain sections of New Orleans and San Fransisco, for example).
As to the demonic nature of so-called aliens, many people who claim to have been abducted speak of this.
Whitley Strieber described it well in "Communion" (he has since recanted).
Then there is the Trickster quality of the so-called aliens. Some people have said that nothing about them is as it seems.
I think it may be overly simplistic to assume the Trickster is a demonic quality exclusively. Jung's description of the Trickster archetype occasionally puts him on the "good" side of the ledger.
That said, the trickster "aliens" seem to lie an awful lot. Because of this, it is probably smart to be wary.