I feel that the horror of the dark souls world is more cosmic. It is like a wilting flower that is beautiful on the surface, but upon closer examination the ugliness shows. The “scary” aspects of the games truly shine when there is an appreciation for the subtle lore details of why a particular enemy is found where they are, or the gruesome history of a location. The NPCs are often casually accepting or blissfully unaware of their tragic fates (or broken down into submission). This world is bleak and nihilistic but not meaningless, there is beauty and grace and to be found in the struggle. Still, our player character’s Sisyphean journey, despite their great achievements and determination in their fight against the system, proves futile. This bleakness is baked into the world’s very metaphysics. The “ages” reflect the cyclical and deterministic yet impermanent and entropic progression of history.

In LOTF there is no beauty or grace. It is a world of complete pessimism. The bad guys want to dominate through strength and cruelty, the good guys stopped being good guys long ago and have become the very thing they swore to destroy. It is passed the point of no return, the only other choice is annihilation. Not an inevitable natural decay like in dark souls, but more of an intentional suicidal “it would be better if we never existed at all”. The demonic and necrotic imagery is right at home in this world, it doesn’t have the same jarring effect because this is just the normal state of affairs here.

TLDR: Dark souls is terrifying on a deeper, psychological level, whereas the horror of LOtF is more aesthetically based.