Aside from an Adventure Time game, we haven’t heard too much from D3 Publisher. In North America, D3 Publisher is associated with the Ben 10 license and Gods Eater series. The company also used to make quirky games in Japan like Zombies vs. Ambulance and the Earth Defense Force series.
D3 is teasing an announcement for E3 with shooting stars falling in the background. New Bangai-O? I hope so, but these days their Japan team primarily makes Vitamin X visual novels… but then again that’s not the kind of thing D3 would announce for North America.