Ace felt his decision to come to Golden Place and go after the royal family first was right since it gave him many clues and help him snap out his delusion of invisibility.
However, he also had the reason for being too careless because he knew about the problem with the middle sky changing border from all those memories he probed from high-level members of three organizations.
But now that he carefully looked at all the scenarios, he finally saw the issue, things were happening too fast with three giants, and he thought they were probably at their wit's end and this was a desperate attempt to deal with him.
However, after he saw the Golden King's behavior and the way he was so calm when he left the golden palace, he finally felt something was amiss and this was a huge conspiracy going behind the sham of desperation.