Catastor vs Kristya

My opponent have 3 Catastor and facedown Solemn Judgment
I have Kristya and facedown Forbidden Chalice and Threatening Roar.
When Catastor's effect activate, I chained it with Chalice which then negated by Judgment.
Can I activated Threatening Roar before the 2nd attack is declared?

Yes.

No, I can't.
or to be precise, I can't found an article or anything about a step/phase after damage step before the game state is open in the battle phase.

You're right. After looking around a bit, I found that you don't have a chance to activate it before your opponent can declare a new attack.

guess we can say answered/locked?