- Many fansites address the Metal Gear Solid 4 character Sunny as "Sunny Gurlukovich," which is her mother's surname. However, the character is only addressed by a single name. According to Metal Gear Rising: Revengeance, her surname is Emmerich, as Otacon became her legal guardian between MGS4 and MGR, although that still poses the question of if Gurlukovich was her surname before adoption or if Sunny even had a last name to begin with.
- Liquid Snake fans seem to more or less agree on his name. It's James, apparently. Though some folks seem to think it to be John since that was Naked Snake's name. To explain the spoiled bit: Zero was the one to put together the project to clone Big Boss. Since his real name is David Oh and we know Solid's real name is David, some believe that Liquid was named after Big Boss, thus John. Where Solidus' name comes from is anyone's guess. Not that anyone cares about Solidus.
- There an alternative theory for this, claiming Liquid's name to be Adam based on the Liquid/EVA exchange in Act 3, going by the notion that David/Zero and Adam/Ocelot were the two closest to Big Boss and practically the ones "responsible" for the Patriots' funding. Solidus, on the other hand, is given John as a name due to being a perfect Big Boss clone, while George Sears is just a false name assumed for his presidency.
- This is also going by the idea that Big Boss's real name is John, which is only said to Ocelot in the end. Every other character that refers to him by name calls him Jack, namely The Boss, who doesn't seem like a person to call someone by a nickname. One idea is that Big Boss probably told Ocelot that his name was John was because he didn't want to give his real name away to an enemy, even if he was relatively friendly. Other than that, we don't have direct conformation that his name really is John or Jack, so this is also fanon.
- Also, the name given to Ocelot was most likely short for "John Doe," the same name Snake gave Para-Medic when she asked for his real name. Given his skeptical response to her saying her name is Jane Doe (and apparently meaning it) he most likely used that name to avoid giving his real one, and the same probably applies to when he said it to Ocelot.
- A new theory that has emerged concerning Liquid's real name has emerged with the trailers for Metal Gear Solid V, which is Eli, the boy briefly shown who would conceivably be the same age Liquid would have been in canon, due to their similarities.
- Some fans speculate that Para-Medic's full name is "Jane Doe Clark," since she tells Snake at one point that "Jane Doe" is her name in Metal Gear Solid 3. Snake doesn't take her seriously, which cause her to remark that she "wasn't kidding."
- The "real names" of the Cobras in Metal Gear Solid 3, while they've fallen out of fashion for fan fiction and comic use recently, were fanon for a while. The names, the most used of which was "Michael" for The Sorrow, were supposedly from an interview with Hideo Kojima that found its way onto a French website and were repeated on several Metal Gear FAQ pages. They were used in the fan comic The Cobra Days, and "Michael" was adopted as "Mikhail" for the Fission Mailed online roleplay. Because there is no evidence of this interview in any official sources, the canonicity of these names is debated.
- The Cobras have a strange draw for Metal Gear fans to the point where they have been given fanon personalities and some backstory elements that show up in multiple stories, comics, and roleplays. For example, The Fury curses constantly, though he doesn't in the game (granted, he only speaks in one scene), and The Fear, when he has a backstory, is almost always of Roma heritage.
Fanon / Metal Gear