When it comes to attacking back, the enemy will be faced with two potential targets, the rider and the monster. The enemy can choose to direct his attacks against either the rider or the monster, and can distribute attacks between them in any way he likes. The opposing player must state how many attacks are against the monster and how many are against the rider before he rolls any dice, otherwise all attacks are assumed to be against the rider.
Attacks are worked out exactly as normal, and the score required to hit will depend upon the relative values of the monster or the rider's Weapon Skill, like all hand-to-hand fighting.