The firing rate of his Gatling guns was too fast, so no matter how many crows the death cultivator could produce, Loki could always shoot them down. As long as the death cultivator can't make more than 200 crows attack him per second, he can always overwhelm the crows with his firepower.
But for some reason, he decided to stop overwhelming the black crowd with his firepower. This allowed one of the black crows to approach him and smash into his head.
This attack looked like a physical attack, but it is actually a spiritual attack. It is a deadly spiritual attack meant to shatter the soul and allow the death cultivator to take over one's body as one of the army of the undead.
Usually, there are very few ways to defend against spiritual attacks, which makes the attack very deadly for most of the populace. In fact, this kind of attack is practically a death sentence for most people, but not for Loki.
