Short answers, pulled from the story.
Jinki: Extend was written and illustrated by Shiro Tsunashima. The series originally ran in Mag Garden's Monthly Comic Blade before moving to Dengeki Moeoh magazine published by MediaWorks after Tsunashima disagreed with the editor-in-chief over the manga's mecha direction in early 2007.
The Jinki: Extend anime television series, animated by the studio Feel, aired from January to March 2005. The 13th episode never broadcast on television and was released as an OVA.
Jinki translates to "man-machine" in Japanese. It refers to the giant humanoid robots that pilots in the series use to fight against the Ancient Jinki, also called Kodai-Jinki.
The story unfolds in two parts. The original Jinki arc is set in Venezuela in 1988, while the Jinki: Extend arc takes place in Tokyo, Japan in 1991.
ADV Films acquired the North American rights to Jinki: Extend for $91,000 and released the series in three volumes and a box set. In 2008, the title was transferred to Funimation along with more than thirty other ADV titles.
The developer Giga produced three adult PC games in the franchise, all featuring art by Tsunashima: Jinki Extend Re:Vision in 2010, Jinki Resurrection in 2020, and Jinki Unlimited in 2022.