|Debut:||Chapter 75; Episode 52 (1999)|
|Occupation(s):||Ten Dons' bodyguards|
|Status:||Ceased to exist|
The Shadow Beasts are a group of the 10 most powerful Nen users within the Mafia Community and are also the the bodyguards of the Ten Dons, supreme leaders of the Mafia. Every year, during the time of the Mafia's underground auction, the Dons gather to discuss their plans and issue orders and the Shadow Beasts are the ones who carry out these orders. Each Shadow Beast has a codename derived from the animal which inspired him to develop his Nen abilities.
On September 1st 2000, after Neon Nostrade predicts that something undesirable will happen at the underground auction in the Cemetery Building, Owl of the Shadow Beasts removes all the auction items from the vault using his Nen ability. Later, all of them are sent by the Dons to deal with the Phantom Troupe, who killed everyone present at the auction. Leech, Porcupine, Rabid Dog and Worm then engage in battle with Uvogin of the Troupe in the Gordeau Desert on the outskirts of Yorknew City. Despite managing to injure him, they are all killed by him. Shortly afterwards, the remaining 6 Shadow Beasts stop 5 Phantom Troupe's members when they are chasing Kurapika and his colleagues and successfully capture Nobunaga. However, they too are quickly killed, except for Owl who is tortured into surrendering the auction items.
Only 5 Shadow Beasts have been mentioned by nickname, and they are: