The evolution of a ZENFORM requires that the Protector has enough skill points which are spent to allow the evoluton to occur. ZENFORMS branch their evolution based on their stats, which are attack, defense and and speed meaning each ZENFORM has the protential to become powerful attackers, strong defenders or swift speedsters.
ZENFORMS have five stages of evolution. The Newborn can progress to Child, Adolescent, Adult and finally to the Grand stage. When evolving a zenform the rank will change, a little bar with stars on it as you can see in battle. The color the bar is shows what stage of evolution a zenform is, newborn is clear, child is green, adolescent is blue, adult is red, but grand is currently unknown.
The Child stage is the second in the evolutionary chain of ZENFORMS. What Child form a Newborn takes relies on its highest Physical Stat. Evolving a ZENFORM to the Child stage costs 1000 SP.
Child stage ZENFORMS evolve into one of four Adolescents depending on their current form and highest physical stat(s) not represented by their form. Evolving a ZENFORM to the Adolescent stage costs 2500 SP.
The Adult stage is dependent on the highest Elemental Stat of the Adolescent. Each Adolescent has four Adult variants. Evolving a ZENFORM to the adult stage costs 5000 SP, according to "How ZENFORMS Evolve".
The method of getting a Grand ZENFORM is currently unknown.