A An Ultimate happens when you attack many foes while rarely being hit. It charges through a special bar, predictably called the Ultimate bar. As you chain attack enemies the blue in the bar rises. When the the bar is filled, you can do an Ultimate, which slows down time so you can rapidly attack enemies and move really fast while your foes can't do anything about it. The screen darkens with blue on the edges when the ultimate is in effect. The ultimate is best used when many enemies are onscreen.