"What is that?" Hal asked and he eyed the vial on the table and could also feel a sort of familiarity with it.
"It's blood. The blood of Beldar the Dystopian)" Tanya said with a serious expression.
(You might remember Beldar to be the Dystopian who wished to make money by supplying body strengthening techniques that turned cultivators into mutated monsters. Chapter 310)
Hal of course remembered Beldar and he also understood what Tanya meant when she referred to using it as an obscure energy source.
That said, he did not act knowledgeable and patiently listened to Tanya's explanation.
"Despite his death, there is powerful nefarious energy within his blood that I have been experimenting with since you brought it to me back then.
I drew the glamour rune with this blood in mind and it is why the rune has a bit of a similarity with spells and is also technically a combination of the two (Spells and Runes).