Can You Blame Me?

The effects of sacrificing Divine Demon Beast Blood was definitely stronger than sacrificing a normal demon beast's blood. However, it was still a temporary loss that could be recovered in the future. As for Fikin, he was sacrificing his Soul Power forever, so it naturally displayed a strength higher than their bloodline sacrifices. 

Nevertheless, three Divine Demon Beasts were up against a single Zasfin, with all of them burning their bloodlines, resulting in another stalemate. Besides, Phex's group could keep burning their bloodlines for much longer than Fikin's Soul Power was able to. If things continued like that, Fikin was bound to die.