Crossbows

Rubi can acquire a pair of pistol-crossbows which fire explosive bolts. Rate of fire is abysmal, even when dual-wielding, but this is compensated for by the explosive power of the bolts. Multiple enemies can be killed in a single blast, making the crossbows something like long-range grenade launchers. They can be upgraded for power and ammo capacity. How Rubi is able to repeatedly fire two single-shot crossbows is a mystery...