The Children of the Lord of Black Pleasures were once a cult to be feared. Nothing was too depraved, no torture to extreme. They might come back once more.
Assassins are always there to be had, for a price. Sometimes, those wishing to hire assassins for very little find their way to the Thrillkill Society.
Many noble lords offend people of equal or greater rank as themselves. In the kingdom of Aoh Chiane, these offenses are dealt with in duels. But, of course, the nobility of Aoh Chiane do not fight their own fights…
Rather than making a baddy impossible to hit, consider giving it mega-hit points.
Super hard to hit leads to great player frustration. Allowing them to do damage leads to a sense of accomplishment. another variation of this would be to give the bad guy a forcefield that shows damage.You could also give them a mastermind ability that sluffs the damage of to minions who should be easy to kill.Once in a while a super high to hit encounter is ok ,but it should be few and far between.
Your mileage may vary