The situation of the attacking undead army was not as severe as Loimos's infiltration of the barrier, as even with so many of them gathered here, they could not simply break in, but the situation was still dire, especially because of the disaster beast, even with the grand roc not being around, there were still eight of them around, and these creatures were far from being simple.
All of them seemed to provide strength to all other surrounding undeads, and each of them seemed to possess some sort of ability capable of affecting livings within the life barrier, The Song's melody was an example of that, and its music alone would severely impede the livings if not for Ansonio countering it.