Here is an excerpt of something that I found online, about Martin Luther, the reformist priest hundreds of years ago, who had experiences with the Devil.

Luther’s world of thought is wholly distorted and apologetically misconstrued if his conception of the Devil is dismissed as a medieval phenomenon and only his faith in Christ retained as relevant or as the only decisive factor. Christ and the Devil were equally real to him: one was the perpetual intercessor for Christianity, the other a menace to mankind till the end. To argue that Luther never overcame the medieval belief in the Devil says far too little; he even intensified it and lent to it additional urgency: Christ and Satan wage a cosmic war for mastery over church and world. No one can evade involvement in this struggle. Even for the believer there is no refuge -- neither monastery nor the seclusion of the wilderness offer him a chance for escape. The Devil is the omnipresent threat, and exactly for this reason the faithful need the proper weapons for survival.

There is no way to grasp Luther’s milieu of experience and faith unless one has an acute sense of his view of Christian existence between God and the Devil: without a recognition of Satan’s power, belief in Christ is reduced to an idea about Christ -- and Luther’s faith becomes a confused delusion in keeping with the tenor of his time.

Attempts are made to offer excuses for Luther by pointing out that he never doubted the omnipotence of God and thus determined only narrow limits for the Devil’s activities. Luther himself would have been outraged at this view: the omnipotent God is indeed real, but as such hidden from us. Faith reaches not for God hidden but for God revealed, who, incarnate in Christ, laid himself open to the Devil’s fury. At Christmas God divested himself of his omnipotence -- the sign given the shepherds was a child "wrapped in swaddling clothes, lying in a manger" (Luke 2:12) . To Luther Christmas was the central feast: "God for us." But that directly implies "the Devil against us." This new belief in the Devil is such an integral part of the Reformation discovery that if the reality of the powers inimical to God is not grasped, the incarnation of Christ, as well as the justification and temptation of the sinner, are reduced to ideas of the mind rather than experiences of faith. That is what Luther’s battle against the Devil meant to convey. Centuries separate Luther from a modern world which has renounced and long since exorcised the Devil, thus finding it hard to see the difference between this kind of religion and medieval witchcraft. But Luther distinguished sharply between faith and superstition. He understood the hellish fears of his time, then discovered in the Scriptures the true thrust and threat of Satan and experienced himself the Devil’s trials and temptations. Consequently he, unlike any theologian before or after him, was able to disperse the fog of witches’ sabbath and sorcery and show the adversary for what he really was: violent toward God, man and the world. To make light of the Devil is to distort faith. "The only way to drive away the Devil is through faith in Christ, by saying: ‘I have been baptized, I am a Christian."’

The following chronicle of his own encounter with the Devil as a poltergeist has a clearly medieval ring:

It is not a unique, unheard-of thing for the Devil to thump about and haunt houses. In our monastery in Wittenberg I heard him distinctly. For when I began to lecture on the Book of Psalms and I was sitting in the refectory after we had sung matins, studying and writing my notes, the Devil came and thudded three times in the storage chamber [the area behind the stove] as if dragging a bushel away. Finally, as it did not want to stop, I collected my books and went to bed. I still regret to this hour that I did not sit him out, to discover what else the Devil wanted to do. I also heard him once over my chamber in the monastery.

The final passage, with its pointed formulation and its underlying expression of contempt for the Devil, was amazing at the time and is overlooked today: "But when I realized that it was Satan, I rolled over and went back to sleep again." It is not as a poltergeist that the Devil discloses his true nature, but as the adversary who thwarts the Word of God; only then is he really to be feared. He seeks to capture the conscience, can quote the Scriptures without fault, and is more pious than God -- that is satanical.

When I awoke last night, the Devil came and wanted to debate with me; he rebuked and reproached me, arguing that I was a sinner. To this I replied: Tell me something new, Devil! I already know that perfectly well; I have committed many a solid and real sin. Indeed there must be good honest sins -- not fabricated and invented ones -- for God to forgive for His beloved Son’s sake, who took all my sins upon Him so that now the sins I have committed are no longer mine but belong to Christ. This wonderful gift of God I am not prepared to deny [in my response to the Devil], but want to acknowledge and confess.

Luther’s purpose is not to spread fear but to strengthen the resistance of the faithful. Like Christ, the Devil is omnipresent. He acts and reacts, is drawn and challenged by anything that smacks of Christ and true faith. Here is found a radical deviation from the medieval concept of the Devil, according to which the evil one is drawn by the smell of sin, the sin of worldly concern. In Luther’s view, it is not a life dedicated to secular tasks and worldly business that attracts and is targeted by the Devil. On the contrary, where Christ is present, the adversary is never far away: "When the Devil harasses us, then we know ourselves to be in good shape!". . .
Now we must listen carefully to Luther and not turn away in embarrassment. Not torture and flames but profession of faith and scorn for the Devil are the proper weapons to use against Hell...
Luther’s autobiography, which appeared in 1545 as the preface to the first edition of his Latin works, has been the subject of exhaustive scholarly research. Nonetheless, Luther is not yet heard out, and his urgent admonition and warning has been missed: "Reader, be commended to God, and pray for the increase of preaching against Satan. For he is powerful and wicked, today more dangerous than ever before because he knows that he has only a short time left to rage."

"Today" means that Luther not only discovered the gospel but also roused the Devil, who is now raging terribly and gaining an unprecedented power of absolutely new satanic proportions.

This is no longer the Devil who, in a triple alliance with "sin" and "world," seduces the voluptuous flesh of man against his better "self." The medieval poltergeist is virtually harmless in comparison with this adversary, who, armed with fire and sword, spiritual temptations and clever arguments, has now risen up against God to prevent the preaching of the gospel. As long as the righteous God resides far away in Heaven, waiting for the end of the world, the Devil, too, will remain at the edge of world history. But the closer the Righteous One comes to us on earth through our belief in Christ, the closer the Devil draws, feeling challenged to take historically effective countermeasures...
The issue is not morality or immorality, it is God and the Devil. This patent encroachment on conscience desecrates the very thing that elevates man above the beasts -- his knowledge of the difference between good and evil. The two great turning points of the Reformation age, the Lutheran and Copernican revolutions, seem to have brought mankind nothing but humiliation. First man is robbed of his power over himself, and then he is pushed to the periphery of creation.

"The Spiritus Sanctus [Holy Spirit] gave me this realization in the cloaca." If this is the site of the Reformation discovery, man’s powerlessness is joined by ignominy. Must the trail of the Reformation be followed this far? There is a dignified way out: by cloaca Luther did not mean the toilet, but the study up in the tower above it. That, however, would be to miss the point of Luther’s provocative statement. The cloaca is not just a privy, it is the most degrading place for man and the Devil’s favorite habitat. Medieval monks already knew this, but the Reformer knows even more now: it is right here that we have Christ, the mighty helper, on our side. No spot is unholy for the Holy Ghost; this is the very place to express contempt for the adversary through trust in Christ crucified.

Christ in the privy helping one to resist the Devil is certainly anything but genteel. In their propriety later centuries recount only how Luther hurled his inkwell across the study at Wartburg Castle. If the Devil must be mentioned, than at least with scholarly decorum. There is no truth in that polite legend, and it masks the actual situation. Bluntly quoting Götz von Berlichingen (immortalized by Goethe in this form: ". . . er kann mich im Arsch lecken" [Faust, act 3]) , Luther attests to the birth of Christ in the filth of this world. The Son of God was truly born into the flesh, into the blood and sweat of man. He understood men because he experienced -- to the bitter end -- what it meant to be human.

As powerful as the Devil is, he cannot become flesh and blood; he can only sire specters and wallow in his own filth. The manger and the altar confront the Devil with the unattainable. Both the demonic, intangible adversary of God and the Son of God are present in the world, but only Christ the Son is corporeally present. Anyone who goes further, making the Devil into a living being, is superstitious. The cloaca is a revealing place. It unmasks the Devil’s powerlessness as well as man’s. Although far removed from propriety, it is the very place of faith, the Christian’s place in life.

Thus the final sentence in Luther’s Rückblick cannot be ignored without suppressing a facet of his belief. Where the gospel is preached and bears fruit, the Devil is there to get in the way --that is his nature, "today" more than ever! Fear of the Devil does not fit in with our modern era, for belief in the Devil has been exorcised by attractive ideologies. But in the process our grasp of the unity of man has been lost: living with the real Christ in one’s faith means being a whole person as opposed to an intellect that subscribes to a mere idea of Christ.

The Devil will readily help theologians to "elevate" the zealous, fighting, wrathful, loving God of Israel into the philosophical concept of an "Omnipotent Being."

For Luther the disembodiment of God into an impressive idea is one of the Devil’s decisive misdeeds. Satan may be no doctor of theology, but he is very well trained in philosophy and has had nearly 6,000 years to practice his craft. All the encouraging victories of God which occur prior to the Last Judgment melt under the Devil’s glare. Arguments are of no help against the Devil; only Christ can come to our aid. Satan’s wisdom is thwarted by the statement "the just shall live by faith" -- faith not in an idea but in a God who, under the banner of the cross, is fighting for a world the Devil, too, is trying to conquer. Satan’s power is not unlimited; he must stay within specified bounds, but until doomsday they encompass the whole world.

Citation:
Oberman, Heiko A. "Luther: Man Between God and the Devil:. Religion. 1989. Yale University. Christian Century, Christian Century Foundation. 24 Jan. 1990. http://http://www.religiononline.org/showarticle.asp?title=750/