While Erin challenged the inheritance trial, the two dragon young ladies didn't slow down the pace of dismantling the dragon imprisonment ritual. Just as they mentioned, they must prohibit Chaos from infiltrating the Dark Dragon's soul whether Erin was able to pass the inheritance ceremony before they dismantled the ritual or not. That was why while Erin was going through the trials, they attempted to remove the ritual step by step and cut off the flow of dragon soul power. Meanwhile, they destroyed the connection between two parties entirely, in order to ensure that the dragon soul power was safe and sound.
And that was the start of the problem.
