[Question] Customizing Battle Mechanics

So I came across Super Pokemon Eevee Edition recently (cool game. You should check it out), and what I thought was most interesting about the game was the battle system.



As you can see, that battle is heavily customized with four pokémon battling simultaneously, in real time, etc., and I thought, Wow, I'd like to try that kind of stuff in my own games. So I PM'd the creator, DarkDoom3000, asking about it, but he or she hasn't replied yet and I doubt he or she ever will.

Anyway, does anyone know where to start with something like this? As, I'm sure, this would go deeper than just replacing battlebacks and customizing command menus. Thanks ! !

That game was made with RPG Maker 2003, which comes with that battle system built-in.

All RPG Makers come with that battle system actually(- VX and VX Ace not showing allies), only difference is positioning of boxes and enemies and similar stuff.

Ah, thank you. But if I'm using Pokémon Essentials, how would I be able to replace those mechanics with the battle system provided by RPGXP?

You'd have to completely re-do the battle system scripts, which is very hard unless you know what you're doing. Your only alternative is to use RPG Maker 2003

If you're trying to make your own battle system, then you would need to change the script.