Steam Bow

The Steam Bow looks a composite bow with brass "belly" piece where the the arrows are placed. When drawn back the "core belly" lets out a puff of steam and the arrows is let loose at a very high speed that is able to pierce the Kabane heart.
 * image = steambow

The arrows used seem to have explosive tips and are not made out of wood in order to compensate for the pressure and tension of the bow. 蒸氣弓