In the Bible, it says that Jesus said that he would not cast aside any that came to him, what if Lucifer therself knelt before Jesus and asked for forgiveness?
Both Satan and demons know that a time of torment awaits them.
For example, we read:
Matthew chapter 8
[
28] And when he was come to the other side into the country of the Gergesenes, there met him two
possessed with devils, coming out of the tombs, exceeding fierce, so that no man might pass by that way.
[
29]
And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time?
[
30] And there was a good way off from them an herd of many swine feeding.
[
31]
So the devils besought him, saying, If thou cast us out, suffer us to go away into the herd of swine.
[
32] And he said unto them, Go. And when they were come out, they went into the herd of swine: and, behold, the whole herd of swine ran violently down a steep place into the sea, and perished in the waters.
[
33] And they that kept them fled, and went their ways into the city, and told every thing, and what was befallen to the possessed of the devils.
[
34] And, behold, the whole city came out to meet Jesus: and when they saw him, they besought him that he would depart out of their coasts.
Here, we see devils/demons beseeching Jesus to not "torment us before the time" (vs. 29). In other words, they know that there is an appointed time for their torment.
We see this same principle in relation to Satan and his angels.
Again, we read:
Revelation chapter 12
[
7] And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
[
8] And prevailed not; neither was their place found any more in heaven.
[
9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
[
10] And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
[
11] And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
[
12] Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea!
for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
When this yet-future war takes place in the heavenlies, Satan and his angels will be cast down to this earth, and Satan will come down "having great wrath because he knows that he has but a short time" (vs. 12).
Again, Satan and his angels know that there is an appointed time for their torment, and here is their final end:
"
And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are,
and shall be tormented day and night for ever and ever." (Revelation 20:10)
Along these same lines, we read:
"Then shall he say also unto them on the left hand,
Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: " (Matthew 25:41)
Everlasting fire, and NOT redemption, is what has been "prepared for the devil and his angels".
Turning to Mark's gospel, we read:
Mark chapter 5
[
1] And they came over unto the other side of the sea, into the country of the Gadarenes.
[
2] And when he was come out of the ship, immediately there met him out of the tombs
a man with an unclean spirit,
[
3] Who had his dwelling among the tombs; and no man could bind him, no, not with chains:
[
4] Because that he had been often bound with fetters and chains, and the chains had been plucked asunder by him, and the fetters broken in pieces: neither could any man tame him.
[
5] And always, night and day, he was in the mountains, and in the tombs, crying, and cutting himself with stones.
[
6] But when he saw Jesus afar off, he ran and worshipped him,
[
7]
And cried with a loud voice, and said, What have I to do with thee, Jesus, thou Son of the most high God? I adjure thee by God, that thou torment me not.
[
8]
For he said unto him, Come out of the man, thou unclean spirit.
Again, we see the unclean spirit or demon in this man begging Jesus to "torment me not" (vs. 7).
We gain a better understanding of exactly what the demons were afraid of in Luke's account.
We read:
Luke chapter 8
[
26] And they arrived at the country of the Gadarenes, which is over against Galilee.
[
27] And when he went forth to land, there met him out of the city
a certain man, which had devils long time, and ware no clothes, neither abode in any house, but in the tombs.
[
28]
When he saw Jesus, he cried out, and fell down before him, and with a loud voice said, What have I to do with thee, Jesus, thou Son of God most high? I beseech thee, torment me not.
[
29]
(For he had commanded the unclean spirit to come out of the man. For oftentimes it had caught him: and he was kept bound with chains and in fetters; and he brake the bands, and was driven of the devil into the wilderness.)
[
30] And Jesus asked him, saying, What is thy name? And he said, Legion: because many devils were entered into him.
[
31]
And they besought him that he would not command them to go out into the deep.
Same scenario, but with a bit more information.
Again, the devils or demons besought Jesus to "torment me not" (vs. 28) while beseeching him "that he would not command them to go out into the deep" (vs. 31).
The underlying Greek word which is here translated as "deep" is "abyssos", from which we derive our English word "abyss":
https://www.blueletterbible.org/lexicon/g12/kjv/tr/0-1/
This same underlying Greek word is translated as "the bottomless pit" several times in the book of Revelation (Rev. 9:1-2, 11, 11:7, 17:8, 20:1, 3).
Apparently, during his three days and three night in the heart of the earth, Jesus stopped there at some point in time because Paul said that Christ was raised from "the deep" (abyssos):
Romans chapter 10
[
6] But the righteousness which is of faith speaketh on this wise, Say not in thine heart, Who shall ascend into heaven? (that is, to bring Christ down from above)
[
7]
Or, Who shall descend into the deep? (that is, to bring up Christ again from the dead)
[
8] But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach;
[
9] That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
[
10] For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.
Anyhow, NOWHERE in the Bible is redemption offered to Satan or his angels.
I hope that this helps to answer your question.