Orcas are dolphins,they are the biggest species of dolphins. If the Orca and a normal dolphin got in to a fight,the Orca would just snatch it and eat it. For perspective,unless dolphins are in a pod, they can’t kill a great white shark as it is normally bigger and stronger unless it is not fully matured. Orcas can do to sharks the same sharks do to other dolphins. The Orca is bigger,stronger,faster,and way smarter than sharks,so they can straight up kill it and eat it. Even if they were the same size Orcas would still be stronger,faster, and smarter,so the Orca would win.