Most impressive physical feat was injured Kyoukai single handedly annhilating Kaishibou’s entire unit of elite soldiers. That was straight up insane, especially considering how early in the series this happened. Lol.
Most impressive tactical feat was Kanki’s precision strikes against the enemy’s Headquarters, first with Genpo then with Haku Ki Sai. The man literally blindsided everyone on the battlefield without any of the major players even getting a glimpse of him.