Board Thread:General Discussion/@comment-6192846-20140612134000/@comment-6192846-20140809195040

The original translator who used "Jisu" didn't do any research for the Japanese text and wanted to avoid us calling it a "Jizz Tiama" for the obvious sexual connotation. The "ji" sound sometimes is used to simulate a Si or Zi sound (for whatever reason).

A quick google search of the term brings up articles about Ziz and recognizes "Jizu" as the most common spelling for it in katakana. We'll be sticking to "ziz" as the translation.