Diamond (Also 'Peridot', 'Jasper' and 'Yellow DIamond') is an Antagonist of Steven Universe Z. She appears from Chapter 5 and onward.
Diamond is a crazily unstable, but super powerful gem fusion created by all of the Diamond Authority. If Diamond is exists for too long, she will become stuck in her form until her gem shatters under pressure, killing all 3 gems inside. She fights with electricity.