With Adam and Eve destroyed and the machine network in chaos, the Commander orders a full scale invasion to finally end the war with the machines once and for all. 2B and 9S work as a guerilla unit, assisting other units in their fight against the machines. During the battle however, 2B is temporarily disabled by an EMP blast and has to be saved by 9S. To her horror though, 2B's squadmates suddenly turn on her, infected by the same logic virus that claimed 9S earlier. As she and 9S are overwhelmed by the YoRHa forcea, the pair are forced to detonate their black boxes once again to escape.

Waking up on the Bunker, 2B meets with 9S and the pair rush to inform the Commander of what has happened. The Commander, however, doesn't trust them and orders the other YoRHa to detain both 2B and 9S on suspicion of being infected themselves. Before the order is carried out, the other androids are suddenly revealed to be infected as well. 2B is forced to cut down her own allies, learning from 9S that the reason she and him and not infected was due to 9S suspending their data sync earlier after having encountered a glitch. As she helps 9S and the Commander escape the exploding Bunker, the Commander stops them when they reach the flight units. She reveals she too is infected, having been synced up with the server like everyone else. 2B implores her to come with them, but is ordered off the Bunker as it begins to explode.

As she and 9S escape in flight units to the surface, other YoRHa flight units attack them. 2B takes control of 9S' control systems, sending his flight unit somewhere safe as her own is outnumbered and shot down. She records a message for 9S before she crashes and discovers that she has also been infected by the logic virus. 2B stumbles her way through the city ruins, her body slowly shutting down and unable to fight. As more YoRHa ground troops surround her, 2B is saved by A2's intervention. Despite this, 2B knows she is doomed since the Bunker is gone with no back up. She bestows her sword and her memories to A2 in her final moments, imploring her fellow android to take care of the future and everyone else. A2 then impales 2B out of mercy, just as 9S arrives to witness her death.

So I need your help... I need to pick which character to go with... 9s, or a2?...

9s

A2