Municipal Squadron Daitenzin (市立戦隊ダイテンジン, Shiritsu Sentai Daitenjin?) is an adult-only, sentai dōjinshi by Rikudo Koshi, also the author of Excel Saga. Essentially, it is the basis of Excel Saga: Many of the characters designs that appeared in Excel Saga originated from the dōjinshi. In fact, in an interview included with the extra material on the fourth DVD volume of ADV's release, Rikudo states that he created Excel Saga to explore the character of Excel. Municipal Force Daitenzin was later published as normal manga.

Source: Wikipedia