Likely due to her upbringing, Bullet behaves in a very militaristic and literal manner, taking an aggressive approach to almost everything. Underneath her icy and militaristic attitude, Bullet is actually good-hearted; being able to become relatively close with Bang Shishigami. However, since her usual demeanour is unusually ill-tempered and antisocial, most of the cast are generally unaware of her softer side.  Bullet has very little experience in anything that isn't related to combat, warfare or her own personal history. She doesn't feel ashamed of her outfit even when other characters consider her costume to be very revealing, this is mainly because Bullet doesn't even know what is 'normal' attire and is loyal to wearing her military uniform. Bullet also seems unaware about her attractive figure, even when rude characters make direct references to her.

Example of Bullet's English Voice: https://www.youtube.com/watch?v=W0yDCno54-E