Both.
Character's level determines how many mini-arts you can equip on one creature, whereas faction skill determines how powerful the mini-arts are.
For example, you can equip 1 mini art on combat lvl 3 and 4, 2 mini arts on lvl 5-8, and 3 mini arts on higher lvls.
However, with faction skill 0, the mini-arts will be things like +1 attack or +1 defense, as fsp level increases, it will become higher such as +4 attack or +4 defense. |