Not really. I played Dark Souls first and beat it with no guide at all; it was hard at first, but once I mastered it, nothing could stop me (well, except for Orstein & Smough, really). When I later played Demon's Souls, it felt way easier, so I beat it with no problem aside from Impalator, who really got on my nerves.
I did have to use a guide with Dark Souls 2, but not because difficultness, but rather, a very cheap gaming design that punished offline players like me.







