Xiphaem

Arcanism-esque practice in which a physical medium (blood) is saturated with magical projections. Similar in execution to a combination of Ink, Earth manipulation, and Yscigg's Ice. Not strictly Blood-aligned, though much easier for those who are due to their access to larger quantities of blood. Much more energy efficient than other mediums due to being able to tap into latent energy from the blood.
Secondarily, Blood-aligned individuals tend to have a better intuitive sense for the magic. However, this also occurs in 'lowercase-blood' aligned entities with no link to the magical plane (and in fact, is the definition of being blood-aligned rather than Blood-aligned). All Blood-aligned are blood-aligned, but the inverse is not true. Notably, the medium is the user's blood- blood of others can be used if claimed. Eideli alchemy has numerous techniques for preservation of blood, allowing one to bleed into a container for later use. Contaminants introduced from usage can weaken integrity of the xiphaem, reducing efficacy of older blood. Ghouls tend to cycle this older blood into ablative layers above a purer core.
Xiphaem's efficiency primarily stems from the natural human Conceptual Alignment towards blood (and other biological matter that makes up the human body).