Twins Marvin and Wendy - with a slightly modernized design - were sort of like the concierges of Titans Tower for a while in the current TT series. They got attacked by their stray Wonder Dog, who was in reality one of Ares' hellhounds sent to menace Cassie, this was about 7-8 issues ago. Marvin died, Wendy ended up in a coma.
The twins also turn out to be the children of Oracle's nemesis The Calculator, and finding a cure for Wendy was his motivation for playing around with Anti-Life code in the Oracle: The Cure mini.