Soul Eater

Soul Eaters (ソウルイーター) are Mid-Tier undead originating from YGGDRASIL. In the New World, they are known as legendary undead that devastated a city. Ainz primarily uses them as mounts for his undead army.

Background
In the New World, it was stated that three Soul Eaters alone once appeared in a beastman city, killing over one hundred thousand beastmen. To the countries, Maruyama stated that their presence alone is enough to cause a national state level emergency.

Without at least a 3rd-tier magic caster present, even facing them was next to impossible. But at the same time, only someone or group of the heroic level can do anything, so its a crisis for all the surrounding nations to deal with.

Appearance
Soul Eaters are skeletal horses with an aura that shines a light on their chest. They are beasts made out of bones, with tendrils of fog replacing their flesh and blood. The fog sparkled everywhere, pus yellow and emerald green.

Abilities
Soul Eaters have long-range attack skills with many uses. They can receive a temporary power-up buff for killing their target through the skill, making them hard to defeat. In other words, Soul Eaters are undead with an area-affecting ability. Soul Eaters can consume the souls of the deceased for sustenance while also growing stronger the more souls they eat. Soul Eaters can radiate an aura of fear and have the ability to recover their HP with the amount of souls they consume. So long as there is a steady supply of souls to feed, their HP bar would be refilled in no time.

They are capable of killing everyone who smells their breath of instant death. When Soul Eaters appeared in YGGDRASIL, they were almost always on-level encounters. Therefore, chances of a player being downed by an instant death effect would only be one in a hundred or less. That was why a Soul Eater's special ability rarely got the chance to see use.

Trivia

 * Like Death Knights, Soul Eaters are looked upon by New World inhabitants as a legendary undead.
 * Five hundred of Soul Eaters were used as mounts for Death Knights and various Nazarick Guarders during the annual war between the Re-Estize Kingdom and the Baharuth Empire.
 * On the adventurer rating system, Soul Eaters have a difficulty rating estimated at 100 to 150. This would make them equivalent to a level 33 to 50 monster in YGGDRASIL.
 * Ainz is currently experimenting on whether or not the Soul Eaters could remain in the New World permanently through consuming the souls of their targets rather than the need for a corpse as its vessel.
 * In the Anime, no Soul Eaters were present at the Katze Plains Massacre, only Death Knights.
 * One of the members of Corpus of the Abyss rode a Soul Eater.