Board Thread:General Discussion/@comment-38.101.126.133-20180209074821/@comment-4010415-20180215143441

Granaatti wrote: In volume 5 they explained that you need to focus your aura around the area you want to protect so it's not a all time whole body armour like we, or at least I, assumed in previous volumes. This explains why Adam was able to cut Yang's arm off, kill Sienna and other "one shot" kills they will probably do in the future.

My point is that it's very unlikely that Vernal, Raven's most trusted underling, hadn't activated her aura. They did not say that it's not a whole-body thing. It's still a whole body thing, and they don't have to focus it to specific places. Though, they can localize it into an actual shield if they want, like Ren did against the King Taijitu and Cinder did against Ruby's bullets in the Volume 1 premiere.

And they explained how Adam cut Yang's arm off, and it is not because she wasn't focusing her Aura to her arm. It is because she literally ran out of Aura, and Adam's attack did so much more damage than the Aura she had left could take. Here's a link to the source and quotes from Miles and Kerry themselves:

Miles: The Aura is, y'know it's like, we establish in the [...] tournament fights that, like... Yeah, every hit can drop it and some hits can break it. It just so happens that Adam's attack was so badass that, in one hit, it managed to break it and do damage all at once, it was super powerful.

Kerry: Yang had also been fighting off-screen.

Miles: Yeah, exactly. Yeah, that girl, that girl had been through some things! It's not necessarily a sword thing, more just like "Oh, he's strong! Oh, he's a scary man!"

^ Basically, it's like if you have only 40 shield left, and your enemy's attack does 90 damage, the amount of shield you have left can only protect you from 40 points of damage, so you also lose 50 points of HP.