Ace was getting slightly agitated as that phantom, who clearly belonged to the Ancestor of Profane Chains, had seen through the truth behind the Law of Sin.
The Law of Sin was the combination of the Seven Sins, making it a unique law that he acquired through the Law of Evil Occult with the help of the system. He wasn't the one who created it, or he wouldn't have struggled with the Law of Sin, which was a mere part of the God of Evil Occult's Idol.
This also left Ace astounded and terrified of the entity known as the God of Evil Occult, who commands a Unique Law akin to the Law of Sin and Evil Occult!
Although Ace wasn't worried about exposing the Law of Sin as long as the Ancestor of Profane Chains wouldn't see through the Order of Darkness, which was, without any doubt, the most precious source of law within his arsenal.
However, he was still wary of that phantom because he was completely unaware of that latter's true intention or what kind of legacy he had left behind.
