Registeel is a silver and dark gray Pokémon with seven red dots on its face and a short, bulky body. It has small stubby silver feet and hands with three fingers. It also has three small red triangles on its knuckles.
This Pokémon's cry is similar to the sound that Transformers make when they transform from vehicle mode to robot mode.
Registeel resembles a robot because it possesses biological functions and isn't of synthetic origin, it can be inferred that it is an extraterrestrial organism, as it is also described as being composed of metal seemingly "not of this earth."
Registeel also appeared in the popular online game "Epic Battle Fantasy."
Due to type, Registeel is considered to be the strongest of the Regi Trio.
All of the Regis are based on the three Ages of the Past; Regirock being the Stone Age; Regice being Ice Age; and Registeel being Iron Age.
Registeel is the only Regi that says its name when sent in battle according to DP128.
Registeel in Lucario and the Mystery of Mew, however, is the only Regi that does not say its name when speaking.
Registeel along with all of the Klink evolutions and Mega Aggron are the only pure steel type Pokémon.