The piece of blood in Iso's hand was shaped like a star. It was an item that only pure-blooded vampires could create. It showed that they had dedicated their lives to the person to whom they voluntarily gave this item, and it ensured that the person to whom they gave it would become their direct slave.
In short, Iso had offered Atlas something that ensured his own loyalty and that of everyone who would carry his blood in the future by sharing his blood directly.
This was something even Iso's ancestors had never done for Cassandra.
Such loyalty had developed far too quickly and had reached such a high level.
"I cannot accept this," Atlas said suddenly. Of course, he did not want to accept it; taking that item, that piece of blood, would be like making Iso and his descendants his slaves. Atlas was, of course, opposed to this.
How could he do that? Even though he had not known Iso for long, Atlas trusted Cassandra's views and thoughts.
"You must, sir," Iso objected.