Echo and Query are two of Riddler's most loyal henchmen.
Before becoming henchgirls, Nina Damfino was a biker and Diedre Vance worked as a dominatrix at the club Pandora's Box. Later meeting and joining forces, the pair began robbing convenience stores. It was during one such job that they encountered the Riddler, who was at a low point in his criminal career.
Recognizing them as "kindred spirits", the Riddler employed them under his gig and all three began working together, with Echo (Nina Damfino) and Query (Diedre Vance) acting as his personal muscle and bodyguards.
- Echo is one of the random bounties in the Amusement Mile's Gang War (Bounty: Joker & Riddler Allies / Wanted: Joker & Riddler Allies).
- She is one of the possible bosses in Turf War: Team Joker.
- In the Riddler's secret hideout in the Monarch Playing Card Company, Echo and Query assist the hero in defending the Riddler from Deathstroke, who was employed by the Joker to kill him.
- Query and Echo first appeared in Detective Comics Annual #8 (1995).
- Echo is voiced by Jodi Jinks.