When Jarul explain about the Loki DF to Shanks and Gaban.
I just realised that Gaban should already know all of that no?
Having completed their journey as a PK crew that learn the "entire history of the world".....Gaban should have known about Nidhogg, it's history, role and pretty much all info.
Looks like a new info to Gaban? The way the panel imply? Or indeed he knows already.
If not, Roger crew could still have some knowledge missing and not actually know "ALL".