One of the first things I noticed, and I think it's the most important difference, is the medium's constraint on internal monologue. The novel 'Battle Through the Heavines' is absolutely packed with Xiao Yan's thoughts and meticulous descriptions of his alchemical processes and cultivation techniques. The manga can't possibly fit all that in without drowning the panels in text, so it has to show instead of tell. I actually think this is a great adaptation choice. The artist distills those complex, page-long cultivation explanations into a few powerful visual cues—a change in aura color, a specific hand seal, a ripple in the energy around him. You get the sense of power progression without the textbook-level detail. The downside, I suppose, is that some readers who love the granular, almost technical aspects of the novel's power system might find the manga version a bit simplified.
That said, the manga leans hard into its visual strengths for the fights, which are way more dynamic and easier to follow. In the novel, a major battle can stretch across chapters with dense prose, and sometimes I'd lose track of the spatial positioning. Here, you see every flash step and pill flame explosion. Yao Lao's ghostly form hovering behind Xiao Yan, Medusa's terrifying presence—these character designs carry so much weight visually that the novel took paragraphs to establish. The trade-off feels fair. You lose some internal depth but gain incredible clarity and impact in the action. I started with the manga and then went back to the novel, and it was the fights in the comic that made me want to understand all the underlying mechanics described in the text.