Further to what I posted at TOMER DEVORAH
The following all comes from The Modern Erev Rav. There are 56 PDF pages to read, if you have the time.
"THE VILNA GAON DESCRIBES AS WELL EACH CATEGORY OF THE EREV RAV
In his book EVEN SHELOMO, the Vilna Gaon, ztk’l wrote that the selection and purification of Israel will not be complete until the Erev Rav separates from Israel completely, because they (Erev Rav) are very attached to the Jews and the Jews learn from their actions.
And the five types of Erev Rav are:
1- Those that create strife and talk Lashon ha Ra
2- Those who pursue their desires like Prostitution, etc.
3- The swindlers who pretend to be Tzaddikim but their hearts are not straight.
4- Those who pursue honor and build great synagogues to make a name for themselves
5- Those who pursue money and strife
"THE TZADDIK RABBI MECHLE MIZLATCHOV ZT’L REVEALS TO US WONDROUS SECRETS THAT THE SATAN WILL DO BEFORE THE COMING OF THE MASHIACH: THE SATAN WILL MAKE MANY CHASSIDIM, AND THEY WILL INCREASE IN THE WORLD IN THE TENS OF THOUSANDS
Once the Holy Tzaddik Rabbi Mechle Mi Zlatchov, (look in the next paragraph where RASHI SAYS how greatly esteemed this Rabbi was in the heavens) fasted many times when he was already old. His students asked him why he was doing this. The Rabbi told them that the Satan wanted to eliminate the Chassidim from the world, and with many devices he caused the accusations and persecutions against the Chassidim to increase...
"...When the Satan saw that his plan was not succeeding, because he had no strength to eliminate them (The Chassidim), he devised a new scheme. He thought that he would also create many Chassidim, and that they would multiply greatly and they would mix with the true Chassidim that separate themselves from the vanities of the world, and the true Chassidim would be mixed with the false Chassidim. And when I saw what the Satan planned to do, I also fasted many times to eliminate this thought from the Satan, because this is the worst possible situation: That there will be many Kosher looking people, deceivers and one will not be able to distinguish who is authentic and who is false."