Wei Cheng was not afraid of the Blood-eyed Demon Monarch waking up.
In fact, he hoped that the Blood-eyed Demon Monarch would be alarmed, making it easier for him to locate him. After that, all that would be left is to light the incense and start a grand sowing, and when everything is all done, they could each go their own way. Wouldn't that be nice?
Unfortunately, this was simply not possible.
He even thought that, even if they gave it their all to attack, aside from alarming the minions left by Blood-eyed demon lord, they might not alert other alien demons, for instance, the Endless Demon Lord who had been hiding in the Cultivation World until the last war. This includes but is not limited to, the alien demon legions sharpening their swords on Earth, ready to turn things upside down.
It was for a simple reason.