The move that Irou performed here is an actual swordplay move, called "tsubame gaeshi", a move inspired by how swallows can quickly turn its tail (and its direction) mid-flight. (It's also the name of a judo move, but the judo move itself is inspired by the sword move, so.....) And the reason why it's Irou in the artwork, is because the move is created by none other than the legendary real-life samurai Sasaki KojIROU. Pokemon fans might know the move Tsubame gaeshi as the signature move of Swellow. Yes, it's the Japanese name for the move Aerial Ace.