The will to power (German: der Wille zur Macht) is a prominent concept in the philosophy of Friedrich Nietzsche. The will to power describes what Nietzsche may have believed to be the main driving force in humans – achievement, ambition, and the striving to reach the highest possible position in life.
Driven by the desire to become a new Dynast King, Vayne is lauded by friend and foe alike as a devious politician, skillful leader and administrator, and a military genius. Vayne is ruthless, manipulative, and obsessed with power. He allows no distractions or obstacles to his goals, removing them by whatever means needed. Vayne is not a brute, however, and is intelligent and pragmatic in his pursuits, recognizing the value of political pawns he can hold over others by keeping enemies alive or manipulating their actions. Vayne values the legacy and stability of Archadia and House Solidor and will use any means to safeguard them. Though he is stated to have executed two of his brothers for treason, Vayne holds a soft spot for his younger brother, Larsa.
Not unlike a sociopath, Vayne had the drive to achieve his goal. This drive is the Will of Power, of which Nietzsche wrote:
My idea is that every specific body strives to become master over all space and to extend its force (its will to power) and to thrust back all that resists its extension. But it continually encounters similar efforts on the part of other bodies and ends by coming to an arrangement (“union”) with those of them that are sufficiently related to it: thus they then conspire together for power. And the process goes on.
In a very literal sense, Vayne Solidor does this when he becomes The Undying (the final form that Vayne takes by merging with Venat and assimilating components of the Sky Fortress Bahamut into his body after he is mortally wounded by Vaan).
In doing so, Vayne also becomes a literal Übermensch, or “Overman, Superman, Superhuman, Hyperman, Hyperhuman”. But the Übermensch as a concept is:
a goal humanity can set for itself. All human life would be given meaning by how it advanced a new generation of human beings. The aspiration of a woman would be to give birth to an Übermensch, for example; her relationships with men would be judged by this standard.
For the denizens of Rabanastre, we can see Vayne Solidor’s goal for humanity:
“Ivalice will know a new Dynast King, and Man will keep his own history! The tyranny of the Gods is ended! We shall be their puppets no more! The freedom for which we have longed is at hand!”
And in the end, he accomplishes it.
As a side note: what I wrote is something I would’ve liked to see in Final Fantasy and Philosophy: The Ultimate Walkthrough, but the writers weren’t very interested in this type of analysis.