We do not know what a KIKIYAMA is. It is speculated that it is either Madotsuki or a NEET man who just happens to be a game designer on par with Goichi Suda in terms of weird scenario writing.
KIKIYAMA is also the creator of Yume Nikki.
For a very long time, it was thought to the English community that Kikiyama (presumed male) had no form of contact, as his website hasn't been updated, and the only mention of him in public was an interview on a Japanese website (unconfirmed). However, a recent thread on Uboachan revealed that all this time, his email address was available. A member contacted him and asked him whether or not he would updated, and it was confirmed that Yume Nikki would make it past version 0.10, albeit very slowly.
Recently, a link was posted on Uboachan to a MySound profile and Pokebis thinks it's KIKIYAMA. Link here.