Riga is mentioned by Jessy as part of a gang of kittypets who like to cause trouble. She says she knows where he and Ziggy live when Bramblestar suggests they attack the kittypets in order to stop them harassing ShadowClan.
When Victor, Scarlet, and O'Hara appear on the fence, Jessy murmurs that Riga and Ziggy are sure to be somewhere close by. Her words soon prove to be true, with the two kittypets appearing to join in the fight against the ThunderClan patrol.
Riga and Ziggy are named after two kittens that Vicky's sister has.