Arravan said: Why does Louise have Riderman's hook/hand?
Because the attack on her family robbed her of her left hand, which in that world, would have easily been regenerated by 24th century medicine, but it wasn't possible due to the GN-Tau particle poisoning/cellular mutation that's slowly killing her, so she had to get a cybernetic replacement in lieu of a genetic one. Hence, Riderman's hook/hand.