Identity Exposed?

The next day, 

Ace opened his eyes from his slumber and he felt all his fatigue was completely gone. After taking a warm bath, he left his room. 

He was planning to go on a stroll to see the outer blade domain's liveness and some scouting. He didn't take anyone with him because he didn't want to draw any unwanted attention to himself. 

However, unbeknownst to him, there were three pairs of eyes monitoring him very closely from shadows. These demons were completely mixed with a large crowd of demons. 

But how could Ace didn't notice them with his newly fortify soul sense? They were tailing him for a while and with his soul signature, he could easily tell something was amiss with these three soul signatures constantly moving around him. 

'Could they be set up by the Demon King to keep an eye on me?' Ace mused as he pretended he noticed nothing.