@Veshv
I think since Taka was just punching (or flicking?) the bullets, they didn't pierce through fully and do much damage. Tatsuki himself also got punched in the gut too, although he seemed to be playing around.
@ricky_rk7
It's basically "people who are acting as undercover spies in big/important organizations" for Kakerou. Usogui helped create the Karametes by blackmailing powerful people who used the L-file (threatening to reveal their crimes), and forced them to accept spies from Kakerou into their organizations.