As soon as he spots you, he automatically recognizes that you aren't someone who traditionally lived inside the Walls of Paradis. He doesn't understand who you are or where you came from, but he feels the urge to know. After all, he has the ability to fight you with the Attack Titan he holds if necessary.

He walks up to you, keeping a cold face. He didn't know if you were an enemy intruder or not.

"You... who are you? Where do you come from? I've never seen you around here before."