I doubt that. First, no Zahard Princess should have such a slow climb that they could become established as a recurrent threat surrounding the Hell Train--at least nowhere near in the same category as Kaiser (1000+ years) or Sachi (600+ years). Second, seeing as characters were surprised that the Bia Twins were back on the Name Hunt station, they should have long ascended to a higher Floor, and there doesn't appear to be any room for predation past the Name Hunt station. No one really boards on the Mushroom Farm station, FoD doesn't even have a real station, and--for all we know--there are no more stations where one could still pass for a Hell Train predator.

That's a fair point... given some actual thought, I'd say David Hockney best fits the description. He regarded as the strongest D-rank Scout and is someone Sachi can swear by (though the fact that he would never leave Mushroom Farm doesn't help his case).

Since dominating a single Hell Train station didn't disqualify Kaiser, it shouldn't disqualify Hockney. =)

I guess so :P

How about Hoaqi? Soul Hunter maybe?

Nahhhhh, the only people that know about Hoaqin are FUG, Sachi, Boro, Daniel, Aka and Roen. All other Regulars that would have encountered him, would have died on the train 600 years ago.

How about the Gate keeper?? or he is not count as predator?

First, there is not only one Gatekeeper. Second, he appears to be Ranker-level given how everyone unanimously fears him. Third, since their role has nothing to do with the Hell Train, it's doubtful that they would be considered Hell Train's predators.

In fact, not many people from the FoD are likely able to leave FoD, the view from Hell Train reveals nothing about the FoD's true colours, and those that visit FoD are unlikely able to leave--assuming they survive at all. In conclusion, aside from the likes of Hockney who escaped from the FoD, no one is likely to have notoriety associated with the Hell Train and Regulars.

When you think about it, one has to have a certain level of notoriety in order to be considered as a Hell Train predator among Regulars. So even if there are deadlier characters on or around the Hell Train, if no one or only selected few know about them, they wouldn't make a name for themselves.

I guss that left AKA & The Princess Twin

And Hockney, and Daniel, and who knows how many other characters that haven't appeared yet, or that haven't appeared at all because of Hoaqin's demonstration on the Wooden Horse station.