Quote Originally Posted by Wolf Kanno View Post
The Ultimania actually reveals that Vayne killed his older brothers on his father's orders, not for his own self interest. The other thing to think about Vayne's actions is that while he certainly does some dubious acts, if you think about it, Larsa benefits more from his brothers actions than Vayne himself does. If Vayne really wanted to take power if Archades and become the ruler of Ivalice then wouldn't he have also plotted to kill Larsa himself. Gramis himself mentioned that his biggest fear was that the Senators would kill him and Vayne because Larsa would be easier to control. So its not like they were innocent bystanders (I wouldn't be surprised if Vayne didn't even have to plant evidence of an assassination plot by the Senate) and Vayne's own actions help to propel Larsa into active duty and to make him come to his own conclusions about justice and what a good ruler should be. With Vayne gone, Larsa becomes the just Emperor that Archades needs and Vayne has already cleared away both the Senate and Occuria who would try to manipulate him.

I honestly do feel that Vayne was originally intended to be a tragic hero who took the mantle of villain and did all the horrible things that needed to be done just so he can save Ivalice and Archades. I feel we see the transition from an ambiguous calculative figure to the generic power hungry villain only when you reach Sky Fortress Bahamut. Before then he seems genuinely concerned for his brother Larsa and his kingdom while looking at the bigger picture of Ivalice that Venat made him more aware of. Even his official artwork for the game usually depicts him by Larsa's side (who happens to be sitting on a throne) which makes him appear less menacing and evil. If some of these "translated Ultimania" sources are actually true then they imply that Matsuno only left a rough draft of the plot for his staff before leaving, which may benefit my theory that Vayne was meant to be more of a complex figure.
So, Gramis fears that the Senate will murder him and his kids and use Larsa as a puppet. Are these fears justified? Not as far as we know. Vayne's acting at the behest of a paranoid madman. The entire reason a Senate exists is to put a check on the power of the Emperor. If the Emperor's word is absolute, the Senate would be completely pointless. So when the Emperor becomes an insane lunatic ordering you to commit mass murder, you're free to say "no".

Also, it's worth pointing out that Vayne had no reason to kill Larsa, because Larsa wouldn't inherit the throne until Vayne is out of the way, most likely dead. Succession passes from oldest to youngest, remember? Funny how only his older brothers wound up dead.