The question is how bad will the last deceptions be.

Gods words describe it with some reverence. Its not insignificant by any means. After all, its by Lucifer himself. It is also said that no man could stand against Lucifer unless the man is really grounded on the truth of the Bible.

Its like Lucifer himself knows the word better than any Christian. It might feel like having to defend the faith against him as some kind of ultimate test.

I know that to deceive people you dont need much these days. But hey, to deceive "even the elect". You better take God's word very seriously, pay attention and not even think of disrespecting the adversary.