The protagonist, Kristian Emerson, is black Army Ranger officer who had turned to military life to come to terms with being beaten half-to death by a drunk professor in an altercation while in college. While he originally takes the revenge motivation to heart, he eventually turns from potential Kratman hero to atoner 'Father of Sin' after the bloodbath that was the American-Japanese invasion and to prevent both Japan and America from potentially toppling the current regime in a way that could lead to another Afghanistan.
His NCOs, Lisa Bannon and Cameron Masterson are also colorful. Bannon was once a real estate agent who left both her husband and family when they proved incapable of dealing with a turn in fortunes after a Chinese housing bubble pop ruined their real estate deals, and turned to drifting before enlisting. Masterson became estranged from his family in his teens and had wandered the Southwest until enlisting, and while he maintains no contact with his parents, their fame as lawyers who successfully fought the oil companies to hand over dried up wells back to the state to be redeveloped rubbed off on him.
Itami at first plays a slightly nay-man role as he tries to maintain that Japan has the right to develop the Special Region, but his nay-man tendencies give way to the fact to three things; his escape into manga whenever the going gets tough, his hands-off attitude (as hard as it is for the rest of the cast) with Chuka's issues after her family's death because he doesn't have the will to play along with her delusions, and the fact that he and his ex-wife Risa, still love each other despite their divorce.
The side characters also are also interesting as hell, and lend credence to the world that the author built.
Wilbur is an ex-BP surveyor who jumped ship after they planned to drill near his childhood home, and spent most of his post-BP career stopping oil spillages from the wars with ISIS and Iran (two separate conflicts, not "they decided to united ala Tom Clancy). While his original task is to survey for oil, his blooming romance with Yao and the exhaustion with his old life has caused him to start pushing to help the people of Falmart (the actual name of the continent) rebuild after the Earth task force wrecked everything.
Doc is a doctor who decided to pursue a military career after being cured of cancer, and becomes Pina's first friend when he helps her research Earth's culture. However, even though he is not present when the war restarts upon the discovery of Japanese and Americans being kept as slaves, his gift to Pina, a pen, clatters to the ground after Emerson walks away from her after the bloody confrontation over the slaves.
Lumaban is a Marine who had served during the Iranian War, where she screwed up after using a designator for kinetic rod strikes as a binocular for observing a fleeing civilian. While she is annoying for playing Catholic missionary despite orders to the contrary, her unit takes over Chuka's care when Itami orders his own unit to leave her be.
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