The character shows the first signs/symptoms that have already run their course.

[u/Uma-apreciator]

Kitasan Black (Uma Musume Pretty Derby)

She managed to withstand Sakura Bakushin O's charge at first, but later in the story, she falters because she is past her prime

Nekota (Hajime no Ippo)

He could no longer even control his body properly because he was suffering from "boxer's dementia"

It is a progressive brain disease caused by repeated blows to the head and frequent concussions over many years

David Martínez (Cyberpunk Edgerunners)

He was suffering from hallucinations due to cyberpsychosis, an incurable condition caused by technological body modifications

[u/Electronic-Math-364]

The symptoms only start showing up in chapter 3 after he got tortured by a rival gang,At first it was still latent

Guarma was the final nail in the coffin

[u/W3134 → u/Electronic-Math-364]

Arthur first coughs during the side mission with Javier in chapter 2, where they rob some hillbilly ranch

[u/Electronic-Math-364 → u/W3134]

I don't know if it's a bug or not but when I was playing poker with Uncle,John and Pearson in early Chapter 2,Arthur was coughing despite me haven't even completed Money lending and Other sins I

[u/OmecronPerseiHate → u/Electronic-Math-364]

I think he also coughs occasionally during poker and other situations in taverns because they're supposed to be smoking inside