Brain vs. Shalltear, possible future implications

Hey guys huge overlord fan who watched and rereads it all the time. Anyways to the point of the post.

-How does Brain cut Shalltear's pinky finger? She's a lvl100 with her fingernails being classified as a natural weapon. I feel like even though she may not have invested points into the class tree its still from a lvl100 vs a lvl25-30. The weapon Brain has is also from the new world therefore lacks data to rival a high lvl weapon just as the reference Ainz makes during the Gazef duel.

Leading to the second point

-If the author is going to be cutting the series short... Will Ainz die by the new world's martial arts by the last God kin? If these martial arts can overcome the lvl barriers just as Brain vs Shalltear (brain also has no weapon break abilities to my knowledge) whats to say this won't happen to Ainz or another guardian.

-A fair counter point is that the breaker lord was unable to break Ainzs weapons although specializing in well name implies. Or am I just over thinking this and its a plot hole?

Let's have a discussion!