D&C 76

Very little is written in the Bible of the "devil and his angels". But in modern revelation we learn much more regarding Satan and "the sons of perdition". We learn -

"...that an angel of God who was in authority in the presence of God, who rebelled against the Only Begotten Son whom the Father loved and who was in the bosom of the Father, was thrust down from the presence of God and the Son,
26 And was called Perdition, for the heavens wept over him—he was Lucifer, a son of the morning." (Doctrine and Covenants Section 76:25 - 26)

Lucifer means "light bearer" or "shining one" and perdition means "loss or destruction". I think the words -

"...he is fallen! is fallen, even a son of the morning!" (Doctrine and Covenants Section 76:27)

...is significant. Even a son of the morning suggests that those who were also sons of the morning were the more valiant in the premortal life. It suggests that even the more valiant can become perdition. But these are they who -

"...maketh war with the saints of God..." (Doctrine and Covenants Section 76:29)

These are they who are so rebellious that -

"...denied the Holy Spirit after having received it..." (Doctrine and Covenants Section 76:35)

even such that -

"...having denied the Only Begotten Son of the Father, having crucified him unto themselves and put him to an open shame." (Doctrine and Covenants Section 76:35)

Which means that these are them that are fully evil, that there is no good left in them at all in that they rebel against all that is good. Of these -

"...there is no forgiveness in this world nor in the world to come..." (Doctrine and Covenants Section 76:34)

because there is no repentance or sorrow, just evil and hate. These are -

"...the only ones on whom the second death shall have any power..." (Doctrine and Covenants Section 76:37)

Which suggest that all others, there is glad tidings that they will be rewarded according to their works and obedience. This is the essence of the gospel.

But of Satan and his followers, they are -

"...the only ones who shall not be redeemed in the due time of the Lord, after the sufferings of his wrath." (Doctrine and Covenants Section 76:38)

"...they shall go away into everlasting punishment, which is endless punishment, which is eternal punishment, to reign with the devil and his angels in eternity, where their worm dieth not, and the fire is not quenched, which is their torment—
45 And the end thereof, neither the place thereof, nor their torment, no man knows;
46 Neither was it revealed, neither is, neither will be revealed unto man, except to them who are made partakers thereof...wherefore, the end, the width, the height, the depth, and the misery thereof, they understand not, neither any man except those who are ordained unto this condemnation." (Doctrine and Covenants Section 76:44 - 48)