Marci

Look to Dispose an enemy in direction of your allies or to slow more enemies on landing.

You can save an ally by using Rebound on him as it provides movement speed bonus.

Many spells and items can kite Marci during Unleash. Counter them with items or choose the right moment to engage and be ready to switch targets.

Blink Dagger is a huge power spike as it allows you to lock on or switch targets, initiate fights or save allies.

Look to play with one of your cores with Sidekick to get kills on the map.

Use Sidekick on your laning partner as soon as you have it to keep a damage and sustain advantage.

Someone should buy spirit Vessel against Marci's Sidekick.

Avoid staying too close to Marci as you'll get Disposed easily.

Kite Marci's ultimate by either stopping her from attacking or disengaging.

Acquire items that allow you to kite Marci's ultimate defensively or offensively.

Items that reduce healing and regeneration are good against Marci's Sidekick.

Items that can dispel Sidekick or Rebound buff from Marci or her ally are great purchase.

Be aware of Marci's Blink Dagger timing. She can easily gap close, setup kills with Dispose or lock on targets during Unleash.