Anima, unlike aether, is not the energy of nature, but the energy of the mind. Rather, the collective minds of all life.
It is said that when an Anima Wielder first perceives their ability, they will see an endless ocean of formless energy and hear a choir of billions...but only for a moment. This endless energy will then flood their minds and overwhelm their [existence], endangering the Wielder to lose their [selves].
But the mind is a resilient thing, and it will automatically create a multifaceted seal to block this flow of energy as much as possible.
It is up to the Wielder than to grow in power and slowly undo these seals, until they can wield the flood.
Anima Wielders go by "locks", there are ten in total.