Yanfly Engine Plugins is a plugin library made for RPG Maker MV, a wonderful piece of software to help you make that role playing game of your dreams. You can find out more about RPG Maker MV here.
You can grab the plugin here:
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This plugin enables you to force a battle advantage on the next upcoming battle, whether it is forced or a random encounter. These advantages can be either pre-emptive strikes, surprise attacks, or even forcing a completely normal battle with no advantage. This plugin also enables specific common events to play upon different battle types.