Card evolutions
Retrained is the term used to describe a monster that has been reprinted with a new effect and slightly different name, but with the same base ATK and DEF, and usually Level as well. Examples include "Battle Ox" to "Enraged Battle Ox" and "Magician of Black Chaos" to "Dark Magician of Chaos". Special cases are Harpie Lady 1, Harpie Lady 2, and Harpie Lady 3, which all have the same stats as the original Harpie Lady, but are not all representing the same creature. Rather, they are the three sisters from Harpie Lady Sisters.
The term "retrained" comes from "Retrained Elf Swordsman," a translation of the Japanese name for "Obnoxious Celtic Guard", who is a retrained version of "Elf Swordsman" ("Celtic Guardian").
Retrained monsters are not to be confused with upgraded ones, such as Cannon Soldier MK-2. These, like retrained monsters, are clearly based on existing cards. However, unlike retrained versions, these have higher ATK and/or DEF and an effect meant to improve upon the original.
Retrained Cards
- Battle Ox -> Enraged Battle Ox
- Magician of Black Chaos -> Dark Magician of Chaos
- Black Luster Soldier -> Black Luster Soldier - Envoy of the Beginning
- Celtic Guardian -> Obnoxious Celtic Guard
- Doll of Demise -> Malice Doll of Demise
- Gaia the Fierce Knight -> Swift Gaia the Fierce Knight
- St. Joan -> Guardian Angel Joan
Upgraded Cards
- Cannon Soldier -> Cannon Soldier MK-2
- Hane-Hane -> Hade-Hane
- Machine King Prototype -> Machine King -> Perfect Machine King
- Man-Eater Bug -> Nobleman-Eater Bug
- Muka Muka -> Enraged Muka Muka
Transformed Cards
- Aqua Madoor -> Neo Aqua Madoor
- Dark Magician -> Dark Sage
- Gigobyte -> Gagagigo -> Giga Gagagigo -> Gogiga Gagagigo
- Harpie's Pet Baby Dragon -> Harpie's Pet Dragon
- Inpachi -> Blazing Inpachi -> Charcoal Inpachi -> Woodborg Inpachi
- Levia-Dragon - Daedalus -> Ocean Dragon Lord - Neo-Daedalus
- Red-Eyes B. Chick -> Red-Eyes B. Dragon -> Red-Eyes Darkness Dragon -> Red-Eyes Darkness Metalic Dragon
- Red-Eyes B. Dragon 2 -> [[
- The Creator Incarnate -> The Creator
- Vampire Lord -> Vampire Genesis
- Warrior of Zera -> Archlord Zerato
- Warrior of Zera -> Mazera DeVille
- Warrior of Zera -> Zera the Mant