I want to create my own manga/story about a specific concept I'm interested in to improve my art skills, but I cannot put my finger on what it is.

I have known there is something in media I love intensely to see and become obsessed with franchises that feature this, but I have no idea what that is. I love things like the SCP, CSM, Touhou, YTTD franchises. They all feature a general thing that I love but I don't actually know what it is.

Your Turn To Die is a creative death game VN. Touhou Project is a bullet hell series of games based on youkai and their powers. SCP is a fictional universe based on the unknown and researching paranormal/supernatural anomalies in reality, and Chainsaw Man (my most recent obsession) is a Manga about a guy who becomes a chainsaw devil, with a universe using devil's and human fear as a concept to push it forward.

I know in my head the similar thing featured in these kinds of universes, but can't name it. All I can think of is that it's body horror or creatively using human psychology generally to push forward a narrative and create an immersive and creative universe and characters, but I know it's not that.

I literally cannot wrack my brain for the answer, no matter how hard I try. Please any advice or answer would be great.

Thank you.