Daisuke and Riku are one of my favorite new couples!  Daisuke is super sweet and clumsy and has an alter ego - "Dark"- who he changes into when he looks at a girl he has feelings for.  Daisuke is initially in love with Riku's twin sister, Risa, but after Risa rejects him, he realizes he and Riku have a lot more in common.  Daisuke clued into his feelings after noticing he turned in Dark when looking at Riku and not Risa.  Riku has always had a crush on Daisuke, but didn't realize it until she became jealous of her sister.

This Relizu cel is of Daisuke and Riku at the end of the series, episode 26.  Riku is relieved Daisuke is safe and they kiss :)