The Ancient Taboo.

The wood elves considered the fight for the plane an investment. But the demon god is making that investment very costly while the first appearance of the ghouls threatened to make the investment a waste. The second coming of the ghouls is the proverbial last nail in the coffin of their ambitions for the plane. 

The Origin gods became silent after arguing. That silence ended until one of them sighed and asked, "So are we of one accord?" 

One of the origin gods replied. "Yes. We will do just like this Ragnarok and go all out. If we can't win, then we must make sure that the demon god wins very little."

Some were quick to reject. "No no no. We vetoed that." 

Someone else rolled their eyes and said. "We are not going to cause further damage to our beloved plane. We are not barbarians."

The origin god wanted destruction and mayhem sighed. "Fine. We will just watch then."