Limit Breaker is an item that increases the level cap of the unit by 10 levels. Since you can only use this item once, you will need more of them to maximize the potential of your best units. Here is how to get Limit Breaker in Anime Defenders.

The best way to get Limit Breaker is through Athenyx Battlepass, which gives you one at level 25 if you have the free version or two if you have Premium Battlepass. To get Athenyx Battlepass, you will need to enter the Athenyx realm, which requires you to be level 30.

You'll need to trade Limit Breakers in Anime Defenders if you need more of these items. There's also always a chance that developers will give them away via Anime Defenders codes, or put them as rewards in Challenges mode.

You can only use Limit Breaker once per unit in Anime Defenders. This means that you can't upgrade your units infinitely. This forces you to spread your resources and invest in more units, which isn't a bad thing. It's more interesting to develop multiple units than to have one dominant unit that would break the game.