Deino is a small blue quadrupedal Pokémon with black fur covering its head and neck, concealing everything but its mouth from view. The fur around its neck also has six purple spots encircling it, which resemble bruises. The hair on the top of its head takes the shape of a single small horn. It also has a short tail that appears to be bitten off. As it is blind, it will bite at and eat anything that moves, and it has the vigor and energy to bite constantly and without stopping. It never stops biting, making it dangerous to approach without taking precautions. It will also ram anything, ensuring that it always has bruises all over it. As seen in The Lonely Deino, it may rear up on its hind legs when happy. Deino primarily lives in caves with abundant water sources.
In the anime
Deino in the anime
Three Deino made their debut in The Lonely Deino! under the care of a Day Care owner named Bobby who was looking after them for their Trainers. Two of the Deino were very rambunctious while one of them was shy and refused to eat. Iris tried to use her experience with Dragon-types to help it feel more comfortable around strangers.
Of all the Pokémon that evolve by level alone, Deino evolves to its final form later than any other Pokémon, evolving at level 64.
Deino also evolves into its second form at level 50, later than any other Pokémon that evolves by leveling up and can evolve again.
No other Pokémon has the same typecombination as Deino and its evolutionary relatives.
Deino is the only Pokémon whose English name's letters are in alphabetical order.
Much like the Deino line's naming pattern, each member of the evolutionary line learns a Normal-type move at level 1 which references the numbers one (Tackle), two (Double Hit) and three (Tri Attack), respectively, which no other member of said line learns.
According to interviews with Ken Sugimori in Nintendo Dream, Deino 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.
Deino may be a combination of dino (short for dinosaur) and ein (German for a, and part of the German for one, eins). It may also derive from δεινός deinos (Ancient Greek for terrible). It may also refer to dinosaurs and other prehistoric animals such as Deinosuchus and Deinonychus. Deino is also the name of one of the Graeae, the three sisters in Greek mythology who shared one interchangeable eye, leaving two blind while one could see.
Monozu may be a combination of mono (prefix meaning one) and 頭 zu (head). Its full name literally means "one head".