Ryu wasn't surprised in the slightest. In fact, the moment Hope suddenly called out like she had, he knew what had happened.
He had put too much effort into bringing Black Worm away and dealing with the other threats for one of them to suddenly sneak up behind him, whether they were far more powerful Sky Gods or not.
From the moment he met Old Wan he understood what kind of person he was. He didn't believe that there was anyone so morally righteous and good that they would leave him be. Other than his eyes, there probably wasn't a single secret on Ryu's body that Old Wan wasn't aware of… of course, that wasn't taking into account new talents that he had formed since he met him.