Nazca acted like he would be some kind of double agent character (with the way he kept snooping around the Sonozaki mansion eavesdropping on their conversations, and otherwise getting significant screentime), but he ended up serving little to no real purpose in the story.
Scorpio in Fourze turned out similarly (long-term ineffectual character), except she stayed a villain. No one even remembered her at the end beyond Ohsugi, and he's too pathetic to count.