Counter Boost makes countering easier and harder-hitting. It needs only level 2, so it is an early pick for players who rely on counters.
Counter Boost sits at position 12 of 18 in the Combat tree. Unlocking Counter Boost takes 2 skill points. You need level 2 before you can buy it. Jacob and Evie each have their own skill tree, so you buy Counter Boost once for each twin.
Adrenaline
Raises how fast your health regenerates.
Combat Stamina
Multi-Kills restore health, more for each enemy killed.
Counter
Press the counter button as an enemy swings to turn his attack back on him.
Execute I
Stun an enemy with Stun Attack, then use a Tool Combo on him to execute him outright.