Lagoon Engine (ラグーンエンジン) is a manga by Yukiru Sugisaki. It's been suggested that this is a prequel to Lagoon Engine Einsatz, but no statements have been made to support this idea.The main protagonists are Yen and Jin Ragun. The name "Lagoon Engine" is derived from the phonetic pronunciation of the main characters' names (Ragun Yen Jin).Volume 6 was released on December 1, 2009. Volume 7 was released in September 2010 in the US.