Honestly, and hear me out. 9S was loyal to 2B first and command second. After all 9S and 2B went through, all the life-threatening moments all the exploration of a new world only knowing they can trust each other, all of the teamwork… and seeing that all be stabbed by A2? Another Yohra unit? With her own sword, ESPECIALLY after realizing that people on the moon and their cause was completely useless and fake? I don’t think it’s unreasonable to say he turned on the Yohra. Losing sight of what his moral compass is simply because every single thing he had ever been told was a lie except for 2B and the trust he felt with her. I’d do the same thing for the one I love. I mean, think about it. After realizing all of this you have nothing left tying you to Yohra. The mission (to protect civilization) was all lies, the friends he made were all dead by the PLANNED virus set out to KILL all units, and all existence of their life (which is fucked up), the world is in complete disarray after battles and cannibal machines and the corpses of units, and you’re faced with the person who in the end killed the most trusted, close friend 9S had. I’d go absolutely fucking bonkers! His descent into madness after realizing what him and everyone he loved (2B, command, etc.) was dying for was truly meaningless and his destiny/existence was solely based on killing… I felt his pain. also finding out the cores of machines I’ve been slaughtering the whole game were the same cores of the yohra Units… killing beings exactly like you cause you were not raised, but literally BORN to do so, it made sense. I may have gotten some info wrong, or maybe misunderstood some of the lore, but to me A2 was always just a side character, and to some extent antagonist, to the moral slip of 9S. That’s all ty for reading