A game trainer is a program made to modify a game's memory and, in turn, its behavior by using different values and addresses so that “cheating” becomes possible.
The Trainer freezes a memory address so the game cannot change or lower the information stored at that address or manipulate the data held at the specified memory addresses so that the person playing can have their needs met.
In the old days, we often referred to these as cheat codes or “cracking” a game. Today it runs separate from the game, barely interrupting the program's normal functioning – and often times accelerating or improving it.
By simplifying the game's side quests and story execution and making it easier to overcome the monsters and bosses, it helps you get even more fun out of your game-playing experience while also helping you develop the skills you need for success!