Cain was confused to see Shura here. The woman should have been far away since even if the fight between him and the Wave King was short, it lasted roughly five minutes.
The fact Shura could appear out of nowhere right after the battle started meant she never went far away in the first place.
Shura did not look at Cain; her eyes focused solely on the old man and the middle-aged woman. Her Essence Wave burst as she stared at the enemies and strengthened her spell.
Although the claw was powerful, the old man had not received much damage from it, and there was a sharp light as he stared at Shura and Cain. As for the middle-aged woman, she was nervous since Shura's reinforcements should arrive at any time, but seeing the resolution in her comrade's eyes helped her calm down.