User blog comment:The ASL Pirates/The Supernovas Where Are They Now?/@comment-24769684-20150515090653/@comment-10543621-20150519070143

Let's summarise the argument:

1. Z is not canon, therefore whatever piece of information provided by him regarding his arm being chopped off by a Shichibukai should not be considered as legit information. Hence in the manga continuity, such an occasion is not considered to have occured, and non of the current or past shichibukai should be seen as having performed such a deed of cutting off the arm from a former Marine Admiral.

2. Although Z is not canon and the things Z said should not be taken as a events that has occured in the manga continuity, we cannot deny the fact that this storyline was written by Oda. Oda himself mentioned that Z is more similar to Shiki in than any of the previous movie only antagonists. Some people choose to believe that like Shiki, Z's character itself could exist even if the movie is non-canon. Even if Z's character doesn't exist in the manga continuity, there is a chance that Oda would draw references in the future of the manga, and spin the story in a way that is consistent with what Z said, without having readers of the manga to have watched the film to understand the reference. A simple exampe would be say IF said shichibukai that cut Z's arm off is Doffy, we could easily have Doffy shout out something before he gets defeated along the lines of "I even defeated a Nave Admiral in the past!!! What are you to me?!!!" Or if it was the mystery 7th Shichibukai, when he does get introduced, someone could easily comment that this guy once fought and injured a Navy Admiral.

So yeah, I think Hanata Sanchou is just trying to say that Z having been completely designed by Oda is definitely close to Oda's heart. Hence purely for thought material, it might be worth considering what Z says as potential hints.