Ral - Running out of juice

She saw Ral up ahead, making a stand from atop a park bench, defending three more children, one of whom cradled a rubber ball with much the same protectiveness that the mother had used for her son. Ral was smiting the metallic warriors, one after another. But Kaya could see that each successive bolt was slightly less intense than its predecessor. Ral’s Accumulator would eventually run out of juice.

***

War of the Spark: Ravnica, Chapter 15