[3.5] How would a wizard make his magic the ONLY magic?

[bihlbo]

In 2E, there was the 12th level spell (and the only 12th level spell ever) Karsus's Avatar, that stole a god's power. Karsus himself cast it on Mystryl, the god of magic, which was a bad idea (Netheril: Empire of Magic and Powers and Pantheons both have more information on the event). When Mystryl was reincarnated to Mystra, she banned all spells that were too powerful.
There's a good reason to decide to go godkilling - You want to be able to cast the immensely powerful spell that can transform you into a god in your own right, and damn the consequences.

I'm not following... How does killing a god allow you to cast a powerful spell that transforms you into a god? Are you referring to Mystra specifically, as in kill her to lift the ban on 12th level spells? Or something else?

[Halinn]

Assuming that a similar deity (or group of deities) in whatever setting you're using is preventing the wizard from using the above epic spell required to achieve godhood, he would want to take out that god (or gods). It would then seem likely that other deities would attempt to stand in his way.
The basic plot is that the wizard needs to eliminate competition, so he can cast his überspell without the petty distraction of meddling deities.

[Endarire]

One option is to just kill/incapacitate everyone he doesn't like.  Wish could do it, GM willing.