This build for veigar is the nightmare for all the other mages on the enemy team! U will need a good tank that can take most of the dameg for u as always.
This build is built on last hitting with "Q" om minnions as much as possible so that u in late game won't have to worrie about your Ability Power or if u loose 1 or 2 stacks on "Soulstealer".

I like this build cuz i think it is a fun build if u meet allot of "AP" Champions. U got a hell lot of damed in lvl 6 and u are so damn fast from 1 place to another so u can be the support and carrier in the team, u don't have allot of hp and it's a good ide to use "Flash" to jump ower walls and other things, And don't forgett to use "Ignite" often for moor AP...

"NOTIS!" If u meet another veigar that u think is better against your build, let him buye the Ability Power so that u will do dameg on him with your ult, if u buye HP and not AP u will be op anyhow against the other Veigar.

So Good Luck and Have Fun!