Monthly Ikki
"G Senjō Heaven's Door" is written and illustrated by Yoko Nihonbashi. It began in the first ever issue of Shogakukan's "Spirits Zōkan Ikki" (re-branded as "Monthly Ikki" in 2003), released on November 30, 2000. The series finished in the August 2003 issue of "Monthly Ikki", released on June 25, 2003. Shogakukan published its chapters in three "tankōbon" volumes, released from March 29 to September 30, 2003. A 3-volume "Complete Edition" was published by Shogakukan between August 12 and October 12, 2016.