Chlorr of the Mask is a character of Garth Nix's Old Kingdom series. She was once a powerful necromancer and Free Magic sorcerer. However, after being bound into Death by the Abhorsen Sabriel , she became one of the Greater Dead. At the beginning of Lirael, she approaches Hedge at the Red Lake, with the aim to command Hedge, as well as the power under the hill (Orannis). However, when she communes with Orannis, It binds Chlorr to Its will instead. For the rest of the series, she is a servant of Hedge. She wears a bronze mask over her face, giving her the name.
Towards the end of Abhorsen, Mogget speaks to Lirael about Chlorr, saying "...even when she was an A--alive." foreshadowing a deeper past. Mogget's unfinished word is presumably "Abhorsen" (or "Abhorsen-in-waiting"), as Garth Nix later reveals more of Chlorr's mysterious past. After they first encounter Chlorr, Mogget and the Disreputable Dog also discuss seeing some sort of indicator around Chlorr which tells them what she is (or was), although they do not remark about what it is. The Dog also reminds Mogget of where his loyalties lie, which shows that she may have held dominion over him once, which means she would have to have been an Abhorsen or Abhorsen-in-Waiting. Mogget also calls Chlorr "Chlorr No-Face", which may have significant meaning.