I Can Feel Your Greed

Sirius had already released his domain earlier upon Adrian's command. The command was to have him release it the moment he appears before the enemies. He also instructed Sirius to create the illusion where the merchants were located. In fact, almost all of the merchants were still passed out and those that could see them being afraid are actually all illusions created by Sirius.

This illusion even affected the perception of the Vice Leader of the Merchant Guild despite his divine blessing which is why his goddess was giving signals to him that Adrian is indeed dangerous. The only ones that are not affected by the illusion is Adrian himself and Piggy Bank since the former told Sirius to take care of the latter. Since the domain has been activated already in a secretive manner, using the most powerful spell in his arsenal was quick and easy.