though it saids they want to adapt it in 26 eps (but still unsure), so it might not be
Well, my hopes, excitement, joy and all these other feels, have just skyrocketed.
I'm just happy to know the amount of episodes those 6 volumes can fill. So all 12 Novels of "2nd Season" adds up to 52 episodes.
There are not 12 novels in the second season, just FYI.
I'm presuming that they'll animate the big one which is Nadeko Medusa and of course Hachikuji's main arc with the darkness but after that it's hard to tell how far they'll go due to the fact that NisiOisiN didn't write the novels in chronological order. We may very well not get the Kanbaru novel until an OVA comes out or something
Frankly, having read them, I really doubt they can do this in 12 episodes. There's just waaaaaaaay too much to cover. Shinobu's joint arc with Hachikuji alone is enough for 12 episodes really, not to mention the whole Hitagi & Nadeko problem is enough for another 12 on their own and god forbid we also get the kanbaru slapped in. It's another KnK mess with the chronology and I assume it will actually come out as a 24 or it'll just end up a sloppy adaptation.
The light novels are grouped by seasons, if I am to understand the structure of the series.
Correct, there will be three seasons and the third season will be the last. That's from the light novel structuring as Nisio put it. Chances are that the anime structure will follow it hereonout but didn't at the beginning (Considering Kizu is a movie instead of a series)