Jack saw the incoming crimson bolt. He did not doubt that this crimson bolt had a knockback effect, which would force him to stop channeling his rune technique. He was powerless about it. If he moved, his rune technique would be canceled all the same.
Before the crimson bolt hit, Alfredo's asura came before him. The asura sent flying by the archdemon was coincidentally in Jack's direction. Seeing that, Alfredo immediately commanded his asura to be Jack's meat shield.
The crimson bolt struck the asura. As expected, it produced a strong knockback force. The asura was pushed in Jack's direction. It bent downward and stabbed its four weapons into the ground to forcefully stopped its skidding.
It managed to stop itself before bumping into Jack.