Zweilous is a dark-blue, quadruped Pokémon with two heads and black fur covering its necks and back. Its front legs are muscular with two claws on each foot, but its rear legs are less defined and have two small, backward-pointing toes without claws. There are tufts of fur over its heads with rounded points at the top. It has two thin wings on its back, each ending in two points. The fur stops at the chest and opens up to fuchsia striped bands on the side of its legs. Though it appears to lack eyes, it is unknown if Zweilous is blind.
Zweilous has the vigor and energy to eat and bite constantly without stopping. Its heads dislike each other and are very hostile. As a result, the heads often turn eating into a competition. Whichever head eats more than the other gets to be the leader. Because of this, Zweilous always eats far too much. It is a nomadic Pokémon; it migrates once it has eaten all the prey in an area.
In the anime
Zweilous in the anime
Major appearances
Zweilous made its anime debut in A Village Homecoming!. Two individuals appeared, with one of them eventually evolving into a Hydreigon.
Zweilous, the Hostile Pokémon and the evolved form of Deino. Zweilous always eats more than it should, moving to a new home after eating all the food it can find.
In the manga
Zweilous in Pokémon Adventures
In the Pokémon Adventures manga
A Zweilous was used by Giallo of the Seven Sages to fend off several Trainers that were trying to rescue the captured Gym Leaders.
Zweilous shares its species name with Basculin. They are both known as the Hostile Pokémon.
Much like its naming pattern, each member of its evolutionary line learns a Normal-type move that involves the number of hits. In Zweilous's case, Double Hit.
Origin
Zweilous is based on the Yamata no Orochi. Its multiple heads and Shiny coloration resemble the Zmey Gorynych, and it may also incorporate elements of the Lernaean Hydra. These mythological serpents may have inspired Hydreigon's Dark typing, as all three are deadly antagonists, with the Zmey Gorynych in particular shown to be deceptive. Due to its apparent blindness and only being found in certaincaves, Zweilous may also be based on a cave salamander.
According to interviews with Ken Sugimori in Nintendo Dream, Zweilous and its evolutionary family were originally intended to be cyborg dragons with aspects of tanks. The Pokémon were scrapped until late in development, when they were revived and remade to be based on Yamata no Orochi. The tank tread-like markings on Zweilous's underbelly are a remnant of this design.
Name origin
Zweilous may be a combination of zwei (German for two) and jealous (as the heads always fight over food). It may also derive from zealous, which reflects Zweilous's voracious appetite and intensely competitive nature.
Dihead is a combination of di (Greek for two) and head.