Mewtwo is a near godlike Pokemon who is very elegant and precise on his decisions. However, he's currently under the control of Darkrai due to his actions of trapping his Sister in the chamber of the Darkest Void, putting her into Eternal Slumber. Mewtwo sounds very deep and elegant, and speaks telepathically, so kind of godlike. And in his third line, he's in a mind controlled state, so make it sound like he's struggling to control himself.