Note: This emblem is outdated.
Mortii is the most populous out of the 4 factions, and is comprised of zombies, ghouls, and fiends. They are "strong" against Faens, and "weak" against Humans. Their ability, Bane, allows them to increase their ATK when attacking a Faen creature.
Mortii creatures are notorious for rarely staying dead. Many of them have Rebirth (and all 3 and 4 star Mortii heroes have Undying, and all 5 star Mortii heroes have Deathless), meaning that they can bring themselves back to life without having to get Revived or Recycled. Also, they are great hero killers, being the only creatures who come with Curse or Godswill.
Mortii comes from the Latin word Mortis, meaning death.