“Question: Is it sinful to want to learn more about ghosts and demons?
Answer: Learning about ghosts and demons is part of our Catholic Faith. The key is not becoming unduly curious about or preoccupied with either, especially demons.
Ghosts are disembodied human beings, something we all become at death. Praying for the repose of the faithful departed and others who have died is a good thing. In addition, asking the prayerful intercession of the saints is also a good thing.
What is not good is seeking out communication with the dead, e.g., through séances. This is an example of divination, which is strictly prohibited (see CCC 2117-19). These are the problematic activities people often have in mind re: learning about ghosts, not praying for the dead, learning about the saints or asking for their intercession.
Demons are fallen angels and thus pure spirits who have irrevocably chosen against God and his people. They are powerful and malevolent, and we must not make ourselves vulnerable to their nefarious machinations.
Rather, we must be wary of their activity and resist them as Sts. James and Peter counsel (Jas. 4:7-8; 1 Pet. 5:6-10). In that light, it’s good to know ourselves and our weaknesses, and how the devil operates in general in trying to lead us away from God, and how he might try to tempt us in particular.
At the same time, we must not become preoccupied with either ghosts or demons. Instead, our minds, as St. Paul reminds us, should be focused on that which is good (Phil. 4:8).”
Summa Catechetica, "Neque enim quaero intelligere ut credam, sed credo ut intelligam." – St Anselm, "Let your religion be less of a theory, and more of a love affair." -G.K. Chesterton, "I want a laity, not arrogant, not rash in speech, not disputatious, but men and women who know their religion, who enter into it, who know just where they stand, who know what they hold and what they do not, and who know their creed so well that they can give an account of it."- Bl John Henry Newman, Cong. Orat., "Encounter, not confrontation; attraction, not promotion; dialogue, not debate." -cf Pope Francis, “You will not see anyone who is really striving after his advancement who is not given to spiritual reading. And as to him who neglects it, the fact will soon be observed by his progress.” -St Athanasius, "To convert someone, go and take them by the hand and guide them." -St Thomas Aquinas, OP. 1 saint ruins ALL the cynicism in Hell & on Earth. “When we pray we talk to God; when we read God talks to us…All spiritual growth comes from reading and reflection.” -St Isidore of Seville, “Also in some meditations today I earnestly asked our Lord to watch over my compositions that they might do me no harm through the enmity or imprudence of any man or my own; that He would have them as His own and employ or not employ them as He should see fit. And this I believe is heard.” -GM Hopkins, SJ, "Only God knows the good that can come about by reading one good Catholic book." — St. John Bosco, "Why don't you try explaining it to them?" – cf St Peter Canisius, SJ, Doctor of the Church, Doctor of the Catechism, "Already I was coming to appreciate that often apologetics consists of offering theological eye glasses of varying prescriptions to an inquirer. Only one prescription will give him clear sight; all the others will give him at best indistinct sight. What you want him to see—some particular truth of the Faith—will remain fuzzy to him until you come across theological eye glasses that precisely compensate for his particular defect of vision." -Karl Keating, "The more perfectly we know God, the more perfectly we love Him." -St Thomas Aquinas, OP, ST, I-II,67,6 ad 3, “But always when I was without a book, my soul would at once become disturbed, and my thoughts wandered." —St. Teresa of Avila, "Let those who think I have said too little and those who think I have said too much, forgive me; and let those who think I have said just enough thank God with me." –St. Augustine