Varpa is a female Smoke Knight assigned to Xerxsephnia von Blitzengaard's (aka Seffie's) service. She has lighter red hair than most of the family, and wears metal gauntlets (or possibly has mechanical hands).
Varpa is first seen when of Malek, another Smoke Knight that Seffie's brother Tweedle has sent to keep an eye on our heroine. Evidently her method of “getting in the way” involves a lot of kissing.
Agatha's own Smoke Knight (by Tarvek's release), Violetta, was aware that Smoke Knights were following her, but doesn't until she discovers that one of Dio Zardilev's party was killed and disguised (as Zardilev himself) using Ghost Spider venom, indicating that it was the work of Madwa Korel, a Smoke Knight loyal to Lucrezia Mongfish, aka the Other. Varpa and Tweedle's man are evidently loyal to Grandmother and will set aside other all other assignments to destroy those in the service of the Other.
Varpa also cheese under the name La Fromage Amore.about