After reading over the Reverse Ansem Reports I can kind of explain a bit more about KH2 now. Some of this is new, some of it isn't but it's just a basic recap of all the events before KH2.
-Ansem (DiZ) uses the DiZ outfit to hid himself from Xehanort because he fears that Xehanort, once knowing who he is, will capture and try to do expirements on him because Ansem has mastered the powers of Twilight. The outfit seems to hide any traces of his twilight powers.
-Ansem (DiZ) has been following the Orgs moves for a long time and follows them to Castle Oblivion to try and understand what they are up to and hopefully get rid of some of them.
-Ansem runs into Namine and right away notices she is similar to Kairi and believes that she was born when Sora used the Dark Keyblade to unlock her Heart from inside him.
-After Namine captures Sora, Ansem takes Sora and Namine back to Twilight Town (an area he is using as a base to hide from the Org) and he also gets the help of Riku. Riku is informed about Sora's situation and how they need Roxas (he has to be willing it seems) to fuse with Sora to bring back Sora 100% and have him help Riku defeat the Org and the Nobodies.
-Riku finds Roxas, and is a bit surprised that he can use a Keyblade, he ends up knocking Roxas out and brings him to Ansem. Ansem places Roxas into a Fake Twilight Town, crafted to slowly insert Sora's memories back into Roxas and to help push him towards joining with Sora.
-Axel isn't evil, he never betrays the Org once. When he kills Vexen in CoM he does so because A) Vexen was a traitor and B) Vexen was going to tell Sora about Roxas, which would have put Roxas in danger, and Axel couldn't have that since he cared to much about Roxas.
-Ansem believes that Roxas was created when Sora become a Heartless and the reason Roxas is so powerful and able to use a Keyblade is because Sora gave himself away to the darkness, similar to how Xehanort did.
-Ansem (DiZ) uses the DiZ outfit to hid himself from Xehanort because he fears that Xehanort, once knowing who he is, will capture and try to do expirements on him because Ansem has mastered the powers of Twilight. The outfit seems to hide any traces of his twilight powers.
-Ansem (DiZ) has been following the Orgs moves for a long time and follows them to Castle Oblivion to try and understand what they are up to and hopefully get rid of some of them.
-Ansem runs into Namine and right away notices she is similar to Kairi and believes that she was born when Sora used the Dark Keyblade to unlock her Heart from inside him.
-After Namine captures Sora, Ansem takes Sora and Namine back to Twilight Town (an area he is using as a base to hide from the Org) and he also gets the help of Riku. Riku is informed about Sora's situation and how they need Roxas (he has to be willing it seems) to fuse with Sora to bring back Sora 100% and have him help Riku defeat the Org and the Nobodies.
-Riku finds Roxas, and is a bit surprised that he can use a Keyblade, he ends up knocking Roxas out and brings him to Ansem. Ansem places Roxas into a Fake Twilight Town, crafted to slowly insert Sora's memories back into Roxas and to help push him towards joining with Sora.
-Axel isn't evil, he never betrays the Org once. When he kills Vexen in CoM he does so because A) Vexen was a traitor and B) Vexen was going to tell Sora about Roxas, which would have put Roxas in danger, and Axel couldn't have that since he cared to much about Roxas.
-Ansem believes that Roxas was created when Sora become a Heartless and the reason Roxas is so powerful and able to use a Keyblade is because Sora gave himself away to the darkness, similar to how Xehanort did.