What is the authenticity of the hadiths attributed to the book "The Most Exalted of Kingdoms for the Days of the Mahdi, the King of the Whole World by the Command of Allah, the Sovereign"? Is it correct to say that hadiths are confirmed by real-world events if they mention names of people who appeared at a certain time? What is the authenticity of the hadiths about the Black Banners? And what is the authenticity of the hadith about the lame Roman leader from Canada or Kindah mentioned in the book "Al-Fitan by Nu'aym ibn Hammad"?

If a weak Hadith reports about the unseen and it occurs as reported, this is an indication that strengthens the Hadith but does not definitively prove its authenticity. It could be a coincidence or an inspiration. The Hadiths about the black banners coming from the East are authentic, among them the Hadith of Thawban which mentions the fighting of three over a treasure, then the appearance of the black banners, and the obligation to pledge allegiance to the Mahdi upon his appearance. The treasure referred to is the treasure of the Kaaba, and the Mahdi is Muhammad ibn Abdullah al-Alawi al-Hasani. As for what Nu'aym ibn Hammad mentions in his book "Al-Fitan" about the Roman leader, these are merely narrations and disconnected reports that cannot be used as proof.