To be honest, the idea of the 25th Production and Construction Brigade came to Gawain the moment he realized someone was trying to investigate the Cecil Clan. He can freely and happily admit that a large part of the name comes from his mischievous sense of humor—after all, people from another world wouldn't get the joke related to planet Earth. Gawain has come to terms with the fact that his crazy use of references won't affect his dignity as an ancestor emerging from the tomb. It might even be seen as a deep strategic mind...
But though there's an element of mischief, Gawain believes there's a certain effectiveness in using this method to handle spies infiltrating the territory.
Dead spies indeed pose no threat to the territory, but they also hold no value whatsoever. As for Gawain... he's actually someone who won't overlook any value.
