Jacob was completely shrouded in Derek's spiritual sense, but he did not resist it at all. He simply let the latter test his capability.
After some time, Derek furrowed his brows slightly. Jacob certainly has the power of a Senior Grandmaster. But I noticed there was a hidden aura in him as well. Although I have no idea what it is, it's probably safe to assume that that's his trump card. That's why he's so confident in winning the battle.
"You're only a Senior Grandmaster. How dare you challenge me to a fight? Are you seeking death or do you have some powerful backup?" Derek questioned and sneered.
He was trying to insinuate that he had found Jacob's secret.
Yet, Jacob replied haughtily, "I don't need any powerful backup to defeat you. Feel free to come at me with all you have."
"Hah! How arrogant! I bet I can finish you off with just one hand."