There are 6 types of characters in FFL3: Humans, Mutants, Beasts, Monsters, Cyborgs, and Robots.

Humans and Mutants
stats increase when levels are raised. Can use weapons and armors.

can eat Meat of stronger Beasts to become stronger. Also becomes stronger Beast when levels are raised. Most skilled with martial arts attacks.

can eat Meat of stronger Monsters to become stronger. Can't use weapons or armors, but can use magic. If a character turns into a Monster they have the Talents of the Monster, plus 100% of the HPS and MPS data of the Monster.

advance by installing parts from other Cyborgs and by adding equipment. Weapons & Shields increas Attack and HPS. Helmets and Body armor increase Defense and HPS. Gloves and Boots increase MPS and HPS. When a character turns into a Cyborg they only retain about 30% of their original HPS and MPS, 70% of their original Attack, Agility, and Magic strength, and 20% of their Defense rating.

advance by installing part from stronger Robots and by using capsule parts: HP, Attack, Defense, and Speed. Characters turned into Robots will have all their original stats lowered. They can't use Magic (except Float and Dive).

A character can change to a different type by either eating Meat left by an enemy or installing Parts left by an enemy. The controlling element of the new type is dependant on three things: the controlling element of the character, and the controlling element of the enemy that left the Parts or Meat.