Who wins lategame, Vayne or Kog?

I probably would say Vayne because of invisibility + hard cc + dmg steroid.

5v5 Kog'maw

1v1 Probably the Vayne if they are good. However this is situational.

Depends on the situation.

In a standard teamfight where neither get caught, Kog'maw.

In a teamfight where divers/assassins can reach the backline consistently, Vayne

In skirmishes/duels, Vayne.

?

He may not be in the game, but Kog n' Vayne ain't even in his league.

Duel vayne

Team fight kog

Vayne, she can delete kog with R+Q+auto+auto lategame. Even harder if there's walls nearby.