Kingdom Hearts Riku-ansem voice

The changes in his Dark Aura show the changes in the source of his darkness. in the beginning of KH1, Riku gets his darkness from Maleficent. Maleficent's darkness is green, so Rikus is green too. when he joins with Ansem SoD, Ansem becomes his source of darkness. blue Ansem darkness, blue Riku darkness. its just nomuras way of showing us Riku's change, along with the voice.

it IS very simple to do, even without technology. when me and my brother want to freak out our friends, we say something, at the same time. the effect is exactly like the Riku-Ansem voice - layered with 2 fairly different voices.

 

ansem maked riku evil because he laughed like him when he trys to hits you hahaha :).
for me riku was in control of his body because he used all
dark mode abylities only using ansem darkness he says "my skills..failed me",but after that fight he disappears only to re-appear when kairi wakes up in ansem sod body form but riku,that wanted kairi safety fought with ansem in his body.

 

Spoiler

Ansem might have known about Malificent since he had the heart of Master Xehanort who had met her and told her about the hearts filled with pure light.

Yeah but he was able to use his keyblade when the guardian was summoned later.

 

I always thought it was because of Ansem possessing Riku. I could hear Ansem's voice clearly, even if it is a little quiet.