Reploid

A Reploid, or Repliroid (レプリロイド) in the original Japanese games, from the science fiction video game series Mega Man X, Mega Man Zero and Mega Man ZX, is an android with complete free will and thought processes comparable to that of humans. The term was originally reserved for robots whose design was ultimately derived (or "replicated") from the original Mega Man X design, but throughout the series the term has been extended to cover any android with similar intellectual capacity, like X and Zero, which aren't Reploids due to the fact they are originals (created by Dr. Light and Dr. Wily respectively) but are referred as by common terms.

History
In 21XX, some 100 years after the events of the original Mega Man series and the apparent death of Doctor Thomas Light, an archaeologist named Doctor Cain is excavating one of Doctor Light's laboratories and discovers a capsule containing a highly advanced robot named "X". X represents a substantial jump in robotics technology, so Cain attempts to reproduce X's technology from Light's original work and notes. When he is unable to reproduce the technology perfectly, Cain is forced to invent alternative solutions. All robotic designs based on X's technology have been referred to as "Reploids," since they are imperfect "replicates" of the original X. Despite being the original, X is often referred to as a Reploid, and refers to himself as such.

By the time of Mega Man ZX, set around 200 years after the Mega Man Zero series, Reploids and humans have eventually become one and the same, due to Reploids being given human mortality and humans getting cybernetic implants. This has blurred the lines between humans and Reploids so much that the entire race (both humans and Reploids) is now known as Humanoids.(Nevertheless, Reploids have triangles on the forehead to make a distinction between them and human's)

Mind
In 200X-20XX, robots such as Mega Man were not entirely capable of free will. As an example, Doctor Wily's Robot Masters were capable of limited thought and moral decisions which lead to such things as hobbies and preferences as these aspects were already set in their programming, giving the programmer some kind of status as a god. Wily usually abused this aspect and mostly programmed or reprogrammed his robots to feel extreme hatred for Mega Man.

Reploids however do not possess similar structure in their AI, giving them absolute free will to same extent as human beings have, which allows them to exist as civillians. This however has led to the concept of Reploids becoming criminals or rebels, which leads to the classification as a "Maverick" (known as "Irregular" in the original Japanese).

Body
By default, a Reploid's body is a mimicry of the human body with biomechanical organs and parts. This concept can be thought of as an advanced version of a homunculus. The biomechanical construction allow for human actions and features such as sensory abilities, breathing (displayed by air bubbles while submerged) and consumption, although this also allows for fatigue, pain and exhaustion. However, most Reploids choose to enhance themselves through more mechanical means such as enhanced leg parts and primitive mechanical muscle.

Being a Maverick Hunter, a police- or military-like occupation created to destroy the Maverick threat, requires modifications for basic combat. Some Reploids such as the original Steel Massimo have mechanically enhanced themselves so far that they resemble primitive 20XX mechanics more so than the more advanced 21XX design. Another example of this form of enhancement was used by Vile in all three of his incarnations, where by choice he removed most of his biomechanical organics in order to house concealed weapons or vernier rockets/thrusters inside of his limbs.

Reploid growth is an unpredictable factor, as displayed by Mega Man X ' s Axl, who has matured into a teenager since Mega Man X7, and Mega Man Zero ' s Alouette, who retained an child age throughout the Mega Man Zero game series and retains an adolescent age in the Mega Man ZX series. But Mega Man Zero ' s Andrew suggests they only grow in mind, while the body is modified by themselves or another person to fit the age, unless they were created or modified to be able to age. Zero is considered by fans the oldest Robot in the series, being created in 20XX and believed to have died around 300 years later, with no apparent aging in both Zero and Omega.

Finally, the power of the robotic body is variable, but the majority of Reploids lifting and power capacity far exceeds that of normal humans. Maverick Hunters usually can lift in the proximity of around several thousand pounds, while civilian and normal Reploids are somewhat weaker, but still beyond human strength.

New Generation Reploids
The New Generation Reploids are created in Mega Man X8 from the prototype Axl. Their main purpose is to serve as the workers for a space elevator project, known as Jakob. These Reploids are fitted with a chip that grants immunity from all viruses known at the time, and also permits these Reploids to change the shape of their bodies (like Axl). However, this ends in failure, as the advanced chip also incorporates data from the Maverick Sigma, causing the Reploids to go Maverick at will. It can also be argued if the Sigma Virus (that is Sigma itself) contaminated all the DNA data, thus creating "clones" of Sigma with very different natures.

Lumine, the main supervisor of Jakob, believed himself and all new-generation Reploids to be superior to even the original Reploids, and plotted to destroy both humans and old-generation Reploids alike. Lumine ultimately fails, and the new generation Reploid line was discontinued after the news of Lumine's Maverick status is revealed. It's also implied that the new generation Reploid line (save for Axl, who was nothing more than a prototype, and apparently Colonel Redips, who seemed to have escaped notice) was also destroyed as well.

Notable new generation Reploids are:
 * Lumine
 * Axl (Albeit as a prototype)
 * Colonel Redips

Mutos Reploid
Mutos Reploid (ミュートスレプリロイド) are a kind of Reploids in the Mega Man Zero series created by Neo Arcadia to protect humans. Their designs are based on mythological beings. The word Mutos is a mistranslation of the Greek word Mythos.

Trivia

 * Despite their overwhelming, global presence in the series, no Reploid gained a playable role up until Mega Man X7 with the introduction of Axl.
 * There's only 3 reploids which are base on Zero's general architecture instead of X's: The copy of Zero from Mega Man X2, the Nightmare Zero, and Zero's body from Mega Man Zero series.