https://www.doujinshi.org/book/969829/

Check out my thread for information on raw scans

https://forums.e-hentai.org/index.php?act=ST&f=53&t=196539&st=0#entry4571469

The cover says it is also a Granblue fantasy parody but it looks like it just has idolmaster characters playing as granblue fantasy.

Base +34, mysto0 -6, hondawhr +24, Iam Angry +6, Palaxius +33, sakurasaku -6

https://www.melonbooks.co.jp/detail/detail.php?product_id=196889
https://www.toranoana.jp/mailorder/article/04/0030/49/01/040030490101.html

Base +26, Epion +31

@Ero-Sennin
iM@S and GBF had a few collabs before and Anya is one of the characters made playable in it. Also, the guy in this doujin is Altair, a GBF character.

Base +7, BrianTT +6, freudia +32, coleccionista903 +6, NicheUploader +5, kondoriyano +6, shuntensatsu +14, Ryougi +10, mysto0 +6, Tsutiya +2, Iam Angry +6, balistafreak +3, 2Sin +6, and 2 more...

WTF!? Altair? why? this shit is so random.

Base +6, balistafreak -3, 2Sin -6, BrianTT -6, Ryougi -10, z3r0d34d64 -6, Palaxius +33, player4578 +6

@Overlol: Everyone in the Water element want and need Altair's dick to survive the meta, in a sense.

Base +6, 2Sin +6, z3r0d34d64 +6, Hue_Hue +6, MaulanaMuhammad +6, mysto0 +6, player4578 -6

Oh nice, I really like seeing unexpected pairings. It's much more interesting than the usual Gran X Anyone. I really wonder at the end though. Was it a "It's a dream" scenario, or did she somehow get returned the her world? Kinda bittersweet if it was right after she found love and was getting used the the other world.

Base +6, Palaxius -30, sakurasaku +6, player4578 -6

tl;dr- Granblue has done a number of collaboration events with Idolmaster resulting in idols visiting Granblue for a time. Anastasia gets a frilly Musketeer water element outfit. And Altair's dick.

Base +6, MaulanaMuhammad +6, player4578 -6

Unexpected crossover but who cares when Anya is so hot right from the cover?

Base +6, mysto0 +6, player4578 -6

If anyone's wondering, Altair's a nice bookish guy (though he might not look like it in his art)

Also there's an idol event to end all idol events going on (allowing one to get just about all the female idols; still have to get Ranko the long way); perhaps allowing a happier ending.

Base +7