The easiest way to get this achievement is to pick a character that you like, and keep using them, for the whole game. After each level, you will roll some dice and land on abilities on the board. Your goal is to purchase all these abilities for 1 character. Keep in mind that each tile has a few purchases, so you are asked to land on each tile a few times. Just keeps playing and you will eventually (with some luck as well) be able to purchase every upgrade available for your character.
Note: The currency used is the gold you collect in the game, so a good amount of gold will be needed.