Ethos is the sigil of Decay. It is first introduced by Alnar when he explains to the Defenders about the coming of the Ethos. The Zad, the Ethos, and RaDosian followers are the only beings that use Ethos Stones.
It can combine with other sigils to form attacks involving dark sorcery. It is dubbed the "Shadow Stone" by some, and also is known as Mortagar. There is no mention of whether or not Ethos as an opposite sigil.
As a Warrior Stone, Ethos uses the two bottom horizontal lines. It is not used as a Booster Stone.
- The Zads (Ethos, Dako)