KIKIYAMA is the enigmatic creator of Yume Nikki.
Very little is known about them, due to the scarcity of information regarding their identity and location. To this day, KIKIYAMA remains a mystery. Due to the long period of time since its last version release, Yume Nikki is not expected to be updated ever again. Their website hasn't been updated since 2008.
While KIKIYAMA seemingly gave the permission to Project Yume Nikki, who created merchandise, a web manga and a light novel with different writers and artists, it is nevertheless regularly mentioned by them that KIKIYAMA's thoughts about the game do not necessarily align with the ones of Project Yume Nikki. It is just an interpretation of the game by said writers and artists, which is also why manga and light novel strongly differ from each other.
According to the developers of it, Kikiyama were involved in the creation of YUMENIKKI –DREAM DIARY–.
Official Website
KIKIYAMAHP is KIKIYAMA's official website pertaining to Yume Nikki. It can be found here:
Contact
There is an e-mail address within the "readme" file of the game, which is hosted at their website. It is [email protected].
However, although this address accepts mail, it is unlikely that KIKIYAMA continues to check it for mail. Furthermore, take note that KIKIYAMA may only know Japanese and e-mails that are written in English could be disregarded. KIKIYAMA has also been known to respond very infrequently and any response that is answered will be answered in a very short, straight-forward response. As with everyone, please be respectful when attempting to e-mail KIKIYAMA.