Lagoon Engine revolves around two characters: 12-year-old Yen, and 11-year-old Jin. While Yen's intelligent, calm, and thinks tactically, Jin's hotheaded and rushes into battle.
The Ragun family is dedicated to defeating ghosts, evil spirits, etc. - known as 'Maga' Yen and Jin just happen to the successors of the family, and they have to fight Maga too. In short: Yen and Jin are Gakushi.
Both Yen and Jin have Maga - though not evil maga. Yen's Maga is called Koga, while Jin's maga is named Sora. Koga is good with gathering information, analyzing and remembering things, though he's extremely bad at attacking. Sora has no intellectual power whatsoever, but his attack power is very high.
Lagoon Engine Einsatz (ラグーンエンジン アインザッツ, Ragūn Enjin Ainzattsu, romanized as Lagūnenjin Einsatz in Japan) is a Japanese manga series written and illustrated by Yukiru Sugisaki that has appeared in Newtype USA since October 2004. In July 2005 an announcement was made that ADV Manga would be distributing the series as graphic novels starting November that year;1 one volume was released. It has been suggested that this series is related in some way to the manga series Lagoon Engine by the same author, but no official statement has been made by the author or publishers to support this idea.
Daisuke Kataoka writes of the series,
An unknown world in the distant past... The people of this ancient world once prospered in the warm embrace of the gods, but they forgot those who blessed them and filled their hearts with greed. Their vulgar hubris made a mockery of the gods, forcing them from their place in the heavens. Now, the gods are no longer kind. Raining death and destruction upon the people, these fallen deities threaten to consume the world...2
[1] Anime News Network http://www.animenewsnetwork.com/news/2005-07-17/new-adv-manga ↩
[2] on Blue Blue Eyes. Accessed 2007-1-2. in Newtype USA's August 2004 issue. http://www.freewebs.com/hiryukoryugu/einsatz/story.html ↩