God can, and does forgive everyone. Satan doesn’t want forgiveness. He wants to take over God’s Kingdom.

Because Lucifer was the highest of the created heavenly angels. He was in the presence of God and beheld God in His glory. In spite of that he led a rebellion to usurp God and His authority. So, Lucifer (Satan) was cast out of heaven. Satan's pride and hatred of God causes him to never seem forgiveness.

You cannot forgive evil because evil never changes,it remains evil and uses your forgiveness to further its cause and contrary to what religion tells you there are things that are NOT forgivable.

For one to be forgiven, they must be truly repentant. Lucifer chose his path consciously and never asked for forgiveness. Therefore, it can't be granted to him.

According to theology.

It is unfortunate that in most cases people refuse to forgive and forget and heap past wrongs upon generations

I feel like God forgives Satan, but home boy's gotta be accountable for all the bullshit he's pulling off...
It's also up to Satan to accept God's forgiveness, which is something He'd probably never do because of his blind hatred for the dude.

Kind of a stale mate

because they're fictional characters, they have to do what the writers tell them to

Because finding a new arch nemesis is a real pain in the ass.

God was like "listen dude we can figure this out..."
Devil: NOPE!!
This went on for quite some time.
Later...
God: fine whatever.
Devil: but I need your powers too, how else am I supposed to lure these stupid beings to hell??
God: *sigh* fine...here's my powers.

And thus, my kids, the story began.
The devil has a whopping bigass ego, God was done arguing.

Because he is actually secretly jealous of Satan.

It's up to Satan to repent

Neither exist

Because satan is still just as evil as he was back then.

Because I do not buy into that stuff.

Why would he want too?