The angels have heard of Arad before; they heard of what he has done, and what he could achieve. But none of them had expected him to be such an unhinged monster. To walk into Death's domain, and pick a soul which didn't belong to him, and then leave unscathed. Just how in the nine hells did he pull that off?
They are angels of peace, and they were present on that day. They had seen and felt Arad's presence after his fight with Eris, and they had just realized that he was even scarier than they had felt at that moment. When they saw him at that time, they felt such a dark, eldritch power from him that the universe looked as if it had collapsed on itself around him, but now… that had extended even further.
