[Chaot]

These are taken from Stormbringer5.

Riposte
This occurs only if using two weapons or a weapon and shield.

Not more than once in a round per combatant, a critical parry allows the parrying character to make a riposte with the weapon (or shield) that didn't parry. The riposte is a free attack that does not count against DEX rank position - it occurs in the DEX rank of the parry. This free attack can be parried or dodged, and armor defends normally against it.

Also...

Two Weapons
Two hand-to-hand weapons can be used, rather than one weapon or one weapon and a shield. Moonglum almost always fought this way, counting on his armor and dexterous parries for protection. The weapons need not be of the same class. Any adventurer can be declared ambidextrous, so any fighter can try this style. Skill for the second hand starts at half of the current skill. Make a separate adventurer sheet entry for it.

Besides ripostes, fighting with two weapons offers the advantage of having a second weapon in hand in case of breakage or a fumble. Two weapons can be advantageous in dark places, when a fire brand could be wielded as a weapon and give light by which to sword fight.