Dunder is a voicebank based off the voice samples of Dunder-P himself. Currently he consists of 5 CV UTAU banks and a voice pack, however VCCV and VCV banks are planned to release in the near future.
Dunder is the leader of his school's Z Music Club. He is responsible for planning out the club's activities and recruiting new members. He's a very enigmatic person, and will often dodge questions about himself in conversations, yet in a way where those he's conversing with manage to be unaware that a question was dodged.
Dunder wears a mask with an LED display. He can control what is displayed on said display, showing anything from a JPEG to a playable AAA game. That said, he usually just has it display a solid color, occasionally with a png image on top of it. Nobody has seen Dunder without the mask on, and nobody ever will. It is unclear how it is being worn or how it stays on, all that is clear is that it is not part of his body.
Several demo versions of Dunder's CV voicebanks were released upon the original creation of Z Vocal Project, these banks were early tests of normal and soft banks recorded on a laptop microphone back in 2016. This version of the soft bank can be heard in this cover posted back in July of 2016.
In early 2017, 4 of the banks that made up Dunder_CV were recorded, these being Dunder_Natsu, Dunder_Fuyu, Dunder_Aki, and Dunder_Haru, continuing the theme of seasons present in the original 2 banks. Some time later, it was decided Dunder needed a dark bank. After a bit of mulling over, this bank ended up being named Dunder_Genesis, the creation of the world. It's a stretch, but it somewhat fit with the theme of seasons.
On June 11th, 2017 Dunder_CV was officially released for free, requiring the purchase of a license to use in commercial works. Two videos were released to commemorate this occasion an original demo song and a demo reel showing off the 5 banks.