Moveset
Movesets are defined on a per-character basis in a custom scripting engine developed by Arcsys. These scripts are called BBS.
Although the core battle state manager of Arcsys games is still somewhat of a mystery to us, BBS has since been blown wide open, allowing us to not just alter characters, but create entirely new ones as well.
We highly recommend you read A Sketch of the Arc System Works Engine Script, by pangaea, first.
For the sake of consistency, all example code uses internal Arcsys nomenclature. Game-specific code might be included where deemed necessary.