The Primordya Veiluris was much stronger than both Fate Changers had expected.
At least its size was much bigger than expected and it made sense why it didn't retaliate. The beings who had emerged from the Veil were not the main body of the Primordya Veiluris but merely its 'babies'.
They didn't retaliate with powerful attacks but mostly endured the attacks without moving much.
Dilan and the Eternal Darkness were far away from the Veil but they were still affected by the tremendous pressure that came from the Primordya Veiluris' main body.