Originally Posted by Death Junior
I think Kog'maw could be the main villain. If Malzahar hadn't invited Kog'maw into the league, He would of just kept on eating and getting bigger, until even the institute of war couldn't stop him. In my mind It's either Malzahar or Kog'maw, but Malzahar has a plan, while Kog'maw just constantly wants to destroy everything, by eating everything! So really Malzahar could have prevented a potential apocalypse.
Same thing as Cho'Gath and Kha'Zix. They, however, are more intelligent, and are waiting on the void to make their true strike on the world.