That's a good question: How much of Kafka is Kafka, and how much is Kaiju?
What I hope we don't get is a b.s. internal dialogue and negotiation between Kafka and the thing, where Kafka wins because he's the good guy and wants to be with his friends, or other b.s.
I like the way that Parasyte handled its similar premise: The alien parasite subtly influenced its host's psychology and improved his body to be a braver better fighter, but only viewed it as necessary for its own survival.
If you think the anime is good, it captured the essence of the source webtoon really well.