Hi, welcome to my Veigar guide.
I've been playing this heavy AP assassin ranked for a while now and would like to share my experiences. Veigar is a champion that can insta-burst any champion if played well.
Farming & Killing
Use Baleful Strike to last-hit minions.
This passive gives a permanent +1 ability power if you succesfuly kill a creep with this skill.
You'll also get bonus 1/2/3/4/5 AP for every champion kill even if you don't use this spell to last-hit them.
A correct spell sequence is essential on Veigar.
Using Event Horizon to stun you opponent(s) makes it easier to land Dark Matter. Following this up with Deathfire Grasp > Baleful Strike > Primordial Burst will deffinitly hurt your opponent(s), if not killing them in 1 giant burst.
Pros / Cons & Teamwork
+++One of the best nukers available for 1350 IP
+++Limitless ability power cap
+++Easy farming with Baleful Strike and Dark Matter
+++Hard counter against squishy carries & teams
----Weak early game
----Mostly single-target focus
----Event Horizon is your only built-in defense mechanism.
In teamfights, stay safely behind your team's front line and wait until you are certain to land Event Horizon. Missing this ability will mean you are less likely to deal maximum damage potential on your enemies, resulting in almost certain death.
Runes, Masteries & Summoner Spells
Since Veigar is a heavily AP based assasin, I like to use full ability power runes.
If you do not have these, try using Magic Penetration, Cooldown Reduction or Gold per 5sec runes.
The masteries that I like to use is 21-0-9, focusing on Ability Power, Mana Regeneration and some Cooldown, Vision and Movement Speed.
Flash is strongly recommend, since Veigar has no escapes besides his Event Horizon.
Ignite or Barrier are a good choice with Flash.
Thanks for reading and good luck tiny master of evil!