The idea behind this is to make your initiation very effective instead of your normal initiation with your team you run ahead and activate you ultimate while running to get far behind the opposing team. When your ultimate's blades come to you they will slow and lower the armor of almost there entire team several times and possibly take out squishier champions who get caught heavily. Then you have 3 options: 1 cut off there minion support to make it so if your team loses the fight they wont be able to push the turret without losing some health. 2 attack from the rear and take them by surprise (hopefully) 3 "cleanup" people are likely to run in teamfights when they are low on health. you can stay a short distance behind and "cleanup" any low health opponents.