Has Pope Benedict XVI or Pope St. John Paul II written anything extensively (or even informally supported any author) on the subject of the Antichrist and the end times?
YES! Pope Emeritus Benedict XVI had clearly prophesied the future of the Vatican II Church in line with CCC675, CCC676 & CCC6777.
The future of Vatican II Church according to Pope Benedict XVI.
A restructured Church with far fewer members that is forced to let go of many places of worship it worked so hard to build over the centuries. A minority Catholic Church with little influence over political decisions, that is socially irrelevant, left humiliated and forced to “start over.”
But a Church that will find itself again and be reborn a “simpler and more spiritual” entity thanks to this “enormous confusion.”
“It will become small and will have to start pretty much all over again. It will no longer have use of the structures it built in its years of prosperity. The reduction in the number of faithful will lead to it losing an important part of its social privileges.” It will start off with small groups and movements and a minority that will make faith central to experience again. “It will be a more spiritual Church, and will not claim a political mandate flirting with the Right one minute and the Left the next. It will be poor and will become the Church of the destitute.”
This was the prophesy made 40 years ago on the future of Christianity by a young Bavarian theologian, Joseph Ratzinger.
This future predictions of the Vatican II Church is in line with the vision of Pope Leo XIII in 1884, when he narrated the conversation he heard between God and satan as follows:
The guttural voice, the voice of Satan in his pride, boasted to Our Lord: "I can destroy your Church."
The gentle voice of Our Lord: "You can? Then go ahead and do so."
Satan: "To do so, I need more time and more power."
Our Lord: "How much time? How much power?
Satan: "75 to 100 years, and a greater power over those who will give themselves over to my service."
Our Lord: "You have the time, you will have the power. Do with them what you will."
This conversation affirmed the CCC675,CCC676 & CCC6777 too, as God by His Divine Providence will allow the Catholic Church to be destroy and also give satan more power or more room to penetrates the Church.
As we all know satan cannot destroy the Church founded by Jesus Christ as stated clearly on Matthew16:18:
Thou art Peter, and upon this rock I will build my church, and the gates of hell shall not prevail against it. And behold I am with you all days, even to the consummation of the world.
—Matt 16:18 (Douay-Rheims)
But, God in 1884 clearly gave satan by way of Divine Providence according to Mysterious Plan of God to allow satan to penetrate inside the Church as affirmed by Pope Paul VI "the smoke of satan has entered the Church". This is not to say that satan enter because he has power over Matthew16:18, satan enters by way of God's Providence.
Satan entering inside Vatican Church who had the powerful promised of Jesus Christ in Matthew16:18, is in parallel to God the Father Will on Jesus Christ persecutions, passion and death as the "Head of the Church" for it's glorious resurrection.
The Vatican II Church as the Mystical Body of Christ must suffer the same too, as CCC675,CCC676 & CCC6777 teaches for it to emerge also into a Resurrected Glorious Church, as Pope Emeritus Benedict XVI prophesied as the future Church.
Lastly, there is a "counterfeit church" and it will be set-up by satan himself, as Arch.Fulton Sheen described it perfectly;
Words of Archbishop Fulton J. Sheen (1948):
“[Satan] will set up a counterfeit church which will be the ape of the [Catholic] Church… It will have all the notes and characteristics of the Church, but in reverse and emptied of its divine content.”
“We are living in the days of the Apocalypse, the last days of our era. The two great forces – the Mystical Body of Christ and the Mystical Body of the anti-Christ – are beginning to draw battle lines for the catastrophic contest.”
“The False prophet will have a religion without a cross. A religion without a world to come. A religion to destroy religions. There will be a counterfeit Church.”
“Christ’s Church the Catholic Church will be one; and the false Prophet will create the other.” - Things Accelerate Toward the End – Prophecy of Archbishop Fulton Sheen
And Fr.Stefano Gobbi's Blue Book stated the actions of the "counterfeit church" in destroying the Vatican II Church in the following evil strategies:
the spread of errors which are being propagated,and are often taught by professors of theology in seminaries and in Catholic Schools and which thus acquire a certain character of credibility and legitimacy;
the open public rebellion against the authentic Magisterium of the Church, especially against that of the Pope, who has from Christ the duty of preserving the Whole Church in the truth of the Catholic Faith;
the bad example given by those Pastors, who have allowed themselves to be completely possessed by the spirit of the world and who become propagators of political and sociological ideologies, rather than messengers of Christ and of His Gospe, thus forgetting the mandate received from Him: "Go into the the whole world and preach the Gospel to every creature."
(Fr.Gobbi's Book "To the Priest, Our Lady's Beloved Sons" message#420 page 682)
"The worldwide membership of the M.M.P. now numbers at least 400 cardinals and bishops, more than 100,000 priests, and millions of religious and faithful around the world."
In closing, Pope Benedict XVI gave clarity in his predictions of the future of the Church aligned with Church Doctrine in Catechism, while St. John Paul II gave the vision on the Final Confrontation of the Vatican II Church on the "counterfeit church the Anti-Church" in support of Archbishop Fulton Sheen prophecy on which it clearly stated that satan will set-up a counterfeit church that had entered into Vatican II Church in no less than Pope St. Paul VI describes it in his words "the smoke of satan had entered the Church".
St. John Paul II was very close to Fr.Stefano Gobbi as he concelebrates a number of Holy Mass with St. John Paul II and gave the Marian Movement of Priests His Apostlic Blessings showing His support for the mission of the movement and it's messages.
The Three Bishops who gave IMPRIMATUR to Fr.Gobbi's book namely:
El Cardenal Bernardino Echeverria Ruiz, OFM
Cardinal Daoud’s Imprimatur for Arabic Edition
Cardinal Wu’s Imprimatur for Chinese Edition
IMPRIMATUR (Pronounced im-prim-AH-tur – Latin for “let it be printed.”)
Imprimatur is an official approval from the hierarchy of the Roman Catholic Church stating that a literary or similar work is totally free from error in all matters of faith and doctrine, and hence is acceptable reading for faithful Catholics. Approval is also sometimes indicated by the words Nihil Obstat which mean “nothing hinders”: there is no obstacle to publication. An imprimatur is not given lightly; it follows a thorough review process. It is usually printed on a page at or near the beginning of the work. The name and title of the official church censor or other ecclesiastical authority, and the date that permission was granted, always accompany either declaration.
Regarding prophecy of St. John Paul II on the Final Confrontation; here is what Mama Mary reveals to Fr.Gobbi:
She Reveals Her Plan
In these messages, I also reveal to you my plan in its silent preparation, in its painful realization and in its victorious fulfillment. You are already about to reach the most painful and bloody conclusion of the purification which will take place in these years, before the great triumph of my Immaculate Heart in the coming to you of the glorious reign of Jesus.
This is a plan which embraces this century. In 1917 at Fatima, I anticipated it, as in a prophetic announcement, at the moment when the great struggle between the Woman Clothed with the Sun and the Red Dragon became evident, a struggle which was to last throughout the whole century, as a proud challenge to God on the part of my Adversary, who was certain that he would succeed in destroying the Church and in bringing all humanity to a universal rejection of God.
The Lord has granted him this space of time, because in the end the pride of the Red Dragon will be broken and conquered by the humility, the littleness, and the power of your heavenly Mother, the Woman Clothed with the Sun, who is now gathering all her little children into her army, drawn up for battle.
Now that you are coming to the most painful and bloody years of this great struggle, I have intervened personally in order to form for myself my cohort through the Marian Movement of Priests, which is my work…” (297c-i, Nov. 9, 1984)
"IN THE END MY IMMACULATE HEART WILL TRIUMPH." But, it will Triumph with all the faithfuls who are united with the Pope & Church Magisterium."