Night on the Blood Liar

The Night of Wallachia's Arc Drive.
The part that looks like a black tornado is actually compressed malignant information. It is a swirling mass of information dense enough to have a physical effect, but even if it were merely imaginary, its operation and management would still be proof of the Night of Wallachia's qualification as one of the 27 Dead Apostle Ancestors.
Incidentally, this is the subtitle of the first Melty Blood. It is a metaphor for the horrific tragedy brought about by the Tatari. Speaking of which, because of the fact that Wallachia drinks human blood in such great quantities, it's more accurate to call him a blood-guzzler rather than a bloodsucker.

MB Act Cadenza PS2 Manual: Tsukihime Dictionary