Relic Castle

Hello, I'm fairly new to the whole experience of Pokémon Essentials, but I have started work on a game (Beta is in testing to find quirks and oddities I've missed), but the first major hurdle I've run into is the creation of an item that's important to the game.

The main character gets a sword and I want to make it an item to be used in battle, when used an attack animation will be played for the sword, and non-elemental damage will be dealt to the enemy Pokémon. The sword would upgrade as you progress through the story, and get stronger (this is a simple fix, I'll just have a new item for each sword upgrade).

I'm trying to wrap my head around the best way to get started making this item, since as far as I'm aware, no current item is used on the enemy Pokémon from the bag, so I don't have a point of reference to start from.