Disgaea cameos in a Nippon Ichi game? Expected. A partnership with light novel mag Dengeki Bunko to borrow Boogiepop from Boogiepop Phantom for a PSP dungeon RPG? Didn't see that coming!
And that's what Nippon Ichi pulled off for Zettai Hero Kaizou Keikaku. Their upcoming dungeon crawler includes various Dengeki Bunko character costumes. While the partnership isn't as big as throwing Hatsune Miku in this game, Nippon Ichi is trying to broaden the audience for this new series. Actually, Nippon Ichi worked with Hatune Miku. She (it?) sang songs for Tori no Hoshi: Aerial Planet, a Japan-only gliding game for the PS2.
Here's a summary of the Dengeki Bunko cameos in Zettai Hero Kaizou Keikaku.