i agree with @Akiyukichan, it's getting annoying really. it also bothers me that the kids (actual adults) trust a stranger more than their family member, they should know that stranger danger.
I think that Ririn has the star fragment implanted somewhere in her body because Del relaxes whenever he's near around her. (Also because Bella also called Ririn 'Star' earlier)
He's probably the god 'Kaleid' from the mythology because he got superpowers (fire and air, we never see Del use...