The difficulty of the Souls series is from the punishment of player mistakes. Not blocking, running away, or healing when you're supposed to do so. A perfect example of this is killing the tutorial boss Vanguard in Demon's Souls. The Vanguard is supposed to kill you. But if you play it right you can kill the Vanguard. However, if you make 2 small mistakes or one big mistake you die.
Also when it comes to Dark Souls 1 and especially Dark Souls 2 they have nerfed several bosses and enemies multiple times already. If you want to play the "hardest" versions of Dark Souls 1 or 2 you would need a console and physical copy of the game.
Also when it comes to Dark Souls 1 and especially Dark Souls 2 they have nerfed several bosses and enemies multiple times already. If you want to play the "hardest" versions of Dark Souls 1 or 2 you would need a console and physical copy of the game.