Ajin is very much the sort of series where it’s not so easy to tell the good guys from the bad guys. There are some exceptions (like Kou and arguably Izumi) but for the most part, all of the main characters in this series including the protagonist have done plenty of bad things already. It’s more or less left to the audience to decide who deserves their empathy (or who’s the most fun to cheer for, whichever the case may be).
Tosaki is an especially vexing case, because despite nominally being humanity’s most important hedge against Ajin, he’s knowingly been behind some of the biggest atrocities in the story. So seeing him in the position he’s in now – a prisoner being tortured by the Pentagon goon (that sort of stuff is going to be making a comeback, it seems) – isn’t really enough to make me feel any sympathy for Tosaki. Frankly I think he’s had this and more coming, and his Karmic debt is a long way from paid off.
Was the purpose of Izumi’s backstory, then, to make us reassess our views on Tosaki? It’s certainly a tragic one – her real name was Tainaka Yoko, and she was sold out by her stepfather (it’s implied that he might have molested her as well). Yoko fled and lived on the street, seemingly turning to prostitution, assuming her mother had betrayed her. It’s only after Tosaki collected her as she was dying and played her the final phone call her parents made to the authorities that Yoko realized her mother had actually tried to protect her before she and the stepfather stabbed each other to death. Tosaki told Yoko to take a new name (she chooses her birth father’s name and her mother’s maiden name), and offers her a new life as his last line of defense against Ajin threats.
Well – so what? it certainly isn’t as if Tosaki did this out of the goodness of his heart – he simply seized on an opportunity. There’s no question that Izumi feels considerable loyalty to him, and that he seems to treat her better than the American treats his “dog” of an Ajin, Myers. But the former is Stockholm Syndrome, and the latter – well, that’s just an incredibly low bar. We’ve already seen Tosaki make it clear to Izumi that he wouldn’t hesitate to cast her aside if it became expedient to do so, and I see no reason not to take him at his word.
The practical issue for the moment is whether to try and rescue Tosaki immediately or not. Kei, naturally, is opposed – he wants to move the location of the rebel base before Tosaki tells the Empire where they’re hiding, and then proceed with the ambush of Satou. But Izumi, bless her, is loyal to a fault – and she eventually convinces Kei that only Tosaki knows the Minister’s schedule and is thus vital to the plan. She’s lying of course, and the rescue mission seems to be taking place at the same time that Satou’s attack is about to happen.
It’s galling that Izumi would be willing to throw away perhaps the only chance to take out Satou (though to be honest my money’s still on him anyway) to save a man who’d leave her to die without a moment’s hesitation if their situations were reversed. But given how young and down-and-out she was when she met him, it’s hard not to feel some empathy for her here. Making enemies out of the Americans is probably a bad idea (though they did start it), but Satou is still the main event – and you have to believe some sort of confrontation with him is still likely to come out of all this, one way or the other.