Shortly after conditioning his mental state, Vaan began refining the first drop of Abaddon's ownerless divine blood.
Without any lingering will in it, the divine blood became pure and docile blood energy. It did not resist nor try to defy his calling the moment he operated his nameless blood art, which he later called the Everlasting Blood Refining Art.
In order to refine and assimilate the divine blood, Vaan couldn't introduce it into his body directly, at least not at his present stage in the Everlasting Blood Refining Art.
First, he sliced open a wound on his wrist and allowed his blood to flow. Afterward, with the guidance of divine energy, his blood formed a high-spinning vortex. The drop of divine blood was dropped right into it to be cleansed of impurities.
Of course, Vaan could skip this step by purifying the divine blood with his Nihility Law. However, he would also be missing out on an integral part of the cleansing process.
Dun dun duuun