Winds of Chaos

What happens if player 1 having shieldsman talent use his shield to attack player 2 having riposte talent? Player 2 use riposte and wins the opposed melee test.

Who is the defender here? Can player 1 use the shieldsman talent to gain advantage?

the person initiating the attack is the attacker, and their target is the defender. the attackers using the shield gets no bonus from their shieldsman talent, and (presumably) suffers damage from their target's defense as a result of the riposte talent.

the rest of the table is allowed to point and laugh.