It is crucial to avoid her obliteration damage, as she is immune while doing it, deals plenty of damage and will even heal her if she has saved darkness stacks.
Champions with a lot of vertical mobility like Andro or Drogoz can counter her, as she cannot stay in the air for longand her attacks are projectiles, which are difficult to hit to a flying enemy.
You can counter a lot of high damage ult or abilities with obliterate or your ult. Maxing out at 80% damage reduction if done correctly with cards and timing.