Gallery may contain minor spoilers for A Song of Silver
Hecar is named for HEKATE (or Hecate), who was the goddess of magic, witchcraft, the night, moon, ghosts and necromancy.
She is one of the Argentium Ultras who allied with the Hidden One, and Ultrawoman Lunaram's arch-nemesis.
She is evil, but still retains her silver color. Argentium ultras cannot get colored on the outside.