According to my understanding,
Angels have free will. They can fall. They cannot be redeemed though. Angels have seen God and dwelt with him. When they fall away they cannot be redeemed they are cast out. They can still come and go, as Lucifer does in the book of Job, but they are not among heavens angels. If they break the laws of God too severely they can be cast into the abyss, which is apparently a region in hell. This is where Legion did not want to be sent.
Jesus, who is the Christ, did not die for sins of angels - but for the sins of man. Angels are already in their immortal form. If there is redemption for angels the Bible does not speak to it.
Angels have free will. They can fall. They cannot be redeemed though. Angels have seen God and dwelt with him. When they fall away they cannot be redeemed they are cast out. They can still come and go, as Lucifer does in the book of Job, but they are not among heavens angels. If they break the laws of God too severely they can be cast into the abyss, which is apparently a region in hell. This is where Legion did not want to be sent.
Jesus, who is the Christ, did not die for sins of angels - but for the sins of man. Angels are already in their immortal form. If there is redemption for angels the Bible does not speak to it.