Enemies such as Agents, Seraph or Smith have a high rate of reversal/counter which can deal massive damage. On a high level, this makes offense not the best option, as the more you attack, the greater the window of opportunity for your opponent to counter/reverse. Anticipate a punch or kick, and before it starts you must fully Focus. Take note of the opponent's stance, keeping a view of their hands and feet while still Focused. The precise moment you see the opponent start to move their hands or feet to strike, press [Action] for a guaranteed reversal. The amount of damage dealt to the opponent here can be rewarding, as reversals are the most time sensitive and must be executed precisely during combat -- a misplaced reversal attempt usually leaves you vulnerable.