Counterattack

Time Required: Reaction
Trigger: Varies
Skill: Varies
Requires: You have a melee weapon in hand or a free hand, you are not Prone, and you are adjacent to the provoking foe

When a foe makes a tactical blunder, you can exploit the opening they leave. A Counterattack can be provoked by many actions, but at the very least, the following typically provoke a Counterattack:

Attempting to leave a square adjacent to a foe;
Casting a Spell other than a touch spell when adjacent to a foe;
Making a Ranged Attack while adjacent to a foe;
Standing up from Prone while adjacent to a foe.

A Counterattack may be made as a melee basic attack or an unarmed basic attack.

Panicked, a goblin attempts to flee from Sir Roland. This provokes a Counterattack, and Sir Roland lashes out with his helbarde, hitting an Agility of 21. This is far above the poor goblin's Agility defence, and Sir Roland inflicts 23 damage on the goblin. That goblin won't be running anymore…