Is there a reason why this exists?

Almost everything in this game is fair, but there is one specific combination of effects that are literally just too strong that there's almost no counterplay to if it has enough scaling to its dmg.

AOE Burst damage while at the same time being Invulnerable.

The only champs that can do this are Lissandra, Vladmir, and to an extent Fizz. Not counting Morg or Fiddle with Zhonya, for it's an item everyone can purchase for invulnerability.

Liss is ok, cuz her ult isn't that damaging. Fizz isn't that bad cuz he can miss R, and usually hits only 1 guy. But Vlad. Is just stupid. He 1 hits your whole team for AOE while being invulnerable. That's stupid as hell. Wow.