FFT 1.3 is a fan-made modification of Squaresoft's game Final Fantasy Tactics for the Playstation and Playstation Portable gaming systems. It greatly increases the difficulty of the game and rebalances gameplay mechanics. 1.3 is not a storyline patch and does not affect the game's plot or character development.
This video shows some of the major features present in the 1.3.0.5 update to 1.3, including the Cactuar monsters.