metaphor refantazio synthesis system

The Metaphor Refantazio Synthesis system let’s you team up attacks by having specific pairings of the game’s various lineages taking part in combat. With Synthesis you will be able to pull off special and more advanced versions of skills at the expense of using additional Turn Icons (Metaphor’s action economy) and resources (MP, HP, or money) from all participating allies

There are a couple of main components that dictate what Synthesis skills are available to you at any given time – the skills a character has unlocked on their Metaphor Refantzio Archetypes and the other Lineages (not specific Archetypes, but the general family) that are in your current active party.