Terrain of Magical Expertise features a power-up system that allows you to customize your character. Each character has five power-up slots. These vary in color and thus what kind of power-ups can be equipped for each character.
There are five colors of power-ups. These are blue, green, yellow, red, and purple. Each color has a general boost or ability that it grants. Each character has fixed color slots they can equip. Power-ups are the primary way to alter your character's stats.
Blue, red, green, and yellow all typically increase some combination of HP, attack power, magic attack, defense, or magic defense. Some can also increase your character's speed. Purple power-ups tend to have special abilities. These include preventing status conditions such as curse, encased, paralyzed, and flower. Others may restore 1 hit point at the beginning of that character's turn or grant additional money after combat.
Power-ups can be found throughout the world of Terrain of Magical Expertise or purchased in shops. You can freely swap power-ups amongst your characters even if they are not in your party. But you can only do so at Equipment Towers which can be found in most towns as well as certain areas. They appear as gray obelisks with blue markings on the bottom and various colors on top.