Yani Neko is the worse smoker by a wide margin, based on how she’s portrayed: she is explicitly described as having a severe nicotine addiction, smoking constantly, and centering her whole routine around cigarettes. Bunta Fujiwara is not presented the same way; the source I found identifies him mainly as a tofu shop owner and former racer, without supporting him as the heavier smoker in this matchup.

Quick Scoop

  • Yani Neko: clearly the more extreme smoker, with nonstop smoking and strong cravings.
  • Bunta Fujiwara: not enough evidence in the sourced material to call him the worse smoker here.

In plain terms, if the question is “who is more defined by smoking as a habit,” it’s Yani Neko.