Anima

Anima is best described as “life essence” - it is an energy that every living creature has, and it is anima which provides the scaffolding to hold a soul’s unique pattern. Anima is resistant to being altered by arcane means, and while it can be siphoned from a living creature or a spirit for use in magic, such a process is both difficult and prone to backfiring. However, it is anima that powers nearly all magical forms of healing and even enables the resurrection of a freshly-killed body.
There are some things that both aether and anima can do, which is normally related to the transformation/change of the physical living body. Shapeshifting, healing, regeneration, etc. Innate shapeshifters use their own anima for the changes, since it’s already earmarked with that particular ability as part of its standard skillset; they don’t need extra arcana. (Anima from shapeshifters is particularly valuable for that reason.) Non-native shapeshifters will often take some anima from the creature whose form they wish to assume; this can be voluntary/mutual or … not … in addition to using some arcana to create the change between forms.

Interactions with Other Energies

Anima can channel, shape, and use arcana. Anima is moderately resistant to arcana, and anima itself is resistant to any change that isn’t inherent to itself. Anima is “heavier” than arcana, no less able to be complicated but less prone to the fine vagaries of arcana. It is what holds the blueprints for life and souls, and ultimately, it is living things that wield arcana - not vice versa.
Anima is also moderately resistant to eldritch, but not to a point even approaching immunity. Anima can technically channel and wield eldritch, but doing so is the equivalent of handling infected materials with no gloves - eldritch will swiftly take root and begin converting anima to more eldritch, whether or not the shape of the anima (such as a soul imprint) is retained. It’s thought that anima is only resistant to arcana and eldritch because of its resistance to being changed, rather than being differently resistant to each of them. It is easier for eldritch to convert anima without changing the shape/pattern of the anima than for eldritch to entirely fuck things up, which is why it’s possible to have an eldritch soul after having an anima soul.
For the same reasons, anima is also moderately resistant to abyssal. Anima is somewhat self-repairing/regenerating, though this process is not fast, but it does mean that abyssal’s slow erosion can be tempered or even halted by self-fixing anima. (Halting it would require extra fuel for anima’s regeneration, such as arcana or aether.) Anima can successfully channel and wield abyssal without immediate damage, but the more abyssal is involved (over time or in quantity), the more anima will wear down and begin to lose its details. Anima cannot directly counter abyssal; it can only make itself resistant or dynamically “immune” through rapid self-repair.

Type

Natural