Said to be ten meters tall, the Dark Young are looked upon as horrifying, pitch-black monstrosities, seemingly made of ropy black tentacles with drooling mouths covering their bodies.
Moreover, the Dark Young are described as having iron-like muscles covered in tough rubbery skin. Not even Gazef Stronoff, using one of the Re-Estize Kingdom's five treasures; Razor Edge, was able to harm them in the slightest. Their roots have been turned into a lump of flesh.
Contrary to the Dark Young's nightmarish appearance, they can make adorable goat bleats. Sprouting underneath their bodies are five hoofed legs that look like those of a goat.
The Dark Young are creatures of monstrosity conjured forth by Super-Tier Magic casted by Ainz Ooal Gown upon the masses who died during the summoning. Since it took 70,000 people to summon 5 Dark Young, it can be assumed that in the New World, it requires 14,000 or fewer living sacrifices to summon one per Dark Young.
The Dark Young are considered to be extremely powerful and highly intelligent monsters. It is able to cause fear and insanity in humans around them. The creature's horrific appearance and size was enough to make the Kingdom's soldiers experience unimaginable anxiety, notably even making Gazef Stronoff feel the urge to turn around and run. Although these monsters do not have any powerful special abilities, they were outstandingly resilient. They are capable of moving at great speeds and outrunning warhorses.
When Gazef used two Martial Arts, 'Sense Weakness' and 'Possibility Sense', he came to learn that his slim chance of victory over the Dark Young are impossible, and was unable to detect any weaknesses from it. It is still unclear whether the Dark Young truly had no weaknesses to begin with and any which appeared could not be seen likely because of the overwhelming difference in strength and levels.
- The Dark Young are based on H. P. Lovecraft's Cthulhu Mythos' Outer God Shub-Niggurath's children. The Dark Young act as proxies for Shub-Niggurath in the accepting of sacrifices and spreading of their mother's faith across the world.
- Under normal circumstances, every summoning of the Dark Young would only produce one entity, which was itself a cause for celebration to players. While being able to bring out two of them was considered a rarity, Ainz broke the record by managing to summon five Dark Young, which is the highest number known so far. However, the Dark Young would eventually disappear after a set amount of time passes.
- According to Princess Renner, the total amount of deaths during the Katze Plains Massacre was said to be over 180,000. 70,000 came from the initial casting of the super-tier spell to summon the Dark Young and another 110,000 from their rampage.