The “ending” of Tenet reveals that The Protagonist’s impact reaches far beyond just being recruited for a world-saving mission. We learn that he recruited himself as well as Neil (Robert Pattinson), and even though we don’t see it, we can safely assume that the masked soldier who saved The Protagonist’s life at the opera was either The Protagonist or Neil. The narrative neatly folds on top of itself where you look at the first half with the knowledge that inverted people from the future are affecting events in the past. Of course, as with any time-travel narrative, you start to go cross-eyed if you try to start trying to untangle the various paradoxes, so it’s best to leave those aside.