[Judoh]

At least it's not Kinzo is Battler from the future or Battler is his own grandfather.

I like it.

I'll add my own crackpot theory in response.

Spoiler for sin:

Shannon, or somebody who was aware of Kinzo's favorite author, talked about it a lot with Battler in 1980 as if obsessed with it. Before Battler left he insulted the novel and said it wasn't a mystery. This made Shannon want to prove to Battler that it was a mystery and when he returned she acted it out.