Riku didn't pretend to be Ansem. Riku's heart was engulfed by darkness and Ansem lays dormant inside of him. When Riku 'submits' to the darkness, he takes Ansem's appearance and must wear a blindfold to cover it up. (hence the blindfold we see throughout Kingdom Hearts II and Kingdom Hearts 358/2 Days)
Riku-Ansem is identical to Ansem, which is the Heartless of Xehanort.
Xehanort
SPOILERSAnsem is a scientist who's later known as DiZ. The real Ansem never became a Heartless. Xehanort is Ansem's apprentice and first experiment. Xehanort later named himself Ansem when Xehanort became a Heartless.Xemnas is Ansem's Nobody.So there are two Ansem's (the imposter Xehanort and the real one named DiZ).DiZ uses Darkness, while Xemnas uses Nothingness.Ansem (Xehanort) and Xemnas are two halves of Xehanort.
Technically neither. Xehanort became a Heartless, and that Heartless called himself "Ansem."
No. Xehanort's Heartless (the fake Ansem) looked like Ansem the Wise (the real Ansem) but a lot tanner.
Ansem the Wise is Ansem the Wise, he is nothing else, he pretended to be Diz in Kingdom Hearts 2, and he didn't show in Kingdom Hearts 1, the Ansem you fight in Kingdom Hearts 1 is actually Xehanort's Heartless, Xehanort is Ansem's apprentice, that became a Heartless, and the Nobody of Xehanort is Xemnas. ------------------------------------------------------------------------------------------------- WRONG!!! Xemnas is Ansem's Nobody... Get rid of the x and switch a few letters around and you get ansem's name.... Not xehanort... FYI... ansem was DiZ... AND......... in kingdom hearts you didn't battle Ansem... You didn't battle xemnas... You battled xehanort that was pretending to be ansem... But it turned out that the REAL ansem was just trying to HELP sora... ----------------------------------------------------------------------------------------------------- The first answer was right. Xemnas is Xehanorts nobody. Think about it... they look alike and had somewhat the same goals.
SpoilersXehanort had turned into a Heartless that called himself Ansem and controlled Riku. So technically, yes, it was Xehanort, but then no, it was his Heartless. The point is, the real Ansem was a good guy, not the one controlling Riku.
SpoilerDiZ is Ansem the Wise's undercover persona. Because his apprentice Xehanort distorts Ansem's name, Ansem uses "DiZ" to separate himself from Xehanort, who others believe to be Ansem. The fact that DiZ is Ansem isn't revealed until the end. "DiZ" is an apparent cameo of "Disney" and the abbreviation of "Darkness in Zero."
Xmnas is Xehanort's nobody and Ansem is Xehanort's heartless. So, basically they are all the same guy. Ansem already tried to take over Riku's hearts so they already have a score to settle with him.
It depends on who "Ansem" is, because there are really 3 different "Ansem"':One is the real Ansem the Wise who disguises himself as DiZ because the other 2 Ansem's take his identity.One fake "Ansem" is Xehanort's Heartless, who calls himself Ansem but is really the antagonist of KH1.The third "Ansem" (the second fake Ansem) is Riku-Ansem: after Riku takes off his black blindfold at Memory's Skyscraper in order to gain enough dark power to defeat Roxas, he permanently turns into Riku-Ansem, who is really Riku but now looks like the other fake Ansem and has more combat power.Since all Nobodies are created from the creation of Heartless, Xemnas is the Nobody of Xehanort's Heartless, Ansem.
The one we know of as "Ansem" is Xehanort's Heartless. He shares some characteristics, such as obvious similarities in clothes, but is very different in appearance.
In Kingdom Hearts I, Xehanort, Ansem's apprentice, became a Heartless and impersonated Ansem as an antagonist. In KH2, Ansem actually came in person as Mickey's old friend.