Heavy Blow

Heavy Blow is a Charm in Hollow Knight. It increases an enemy's knockback when hit by Nail strikes or Nail Arts. It also reduces the number of hits required to stagger a boss by 1.

Usefulness
High knockback can be useful for enemies who have an uninterruptible attack, like the Massive Moss Charger and the Wandering Husk. Using Heavy Blow against this kind of enemy usually pushes them back far enough to prevent their attack from hitting the Knight, allowing for more consecutive attacks, a chance to escape and heal, and safer Nail attacks for enemies with high range (thus removing the need for a ranged Spell and saving SOUL). However, this Charm should not be used against ranged enemies and Warrior Dreams such as No Eyes and Gorb (especially considering that they cannot be staggered), as it is harder to deal consistent damage to them from a distance.

Enemies that do not take knockback are not affected by Heavy Blow's increased knockback. This includes most bosses.

Since Heavy Blow decreases the hits needed to stagger a boss by 1, it can be useful during boss fights.

How to Acquire
Bought from Sly for after bringing him the Shopkeeper's Key found in the Crystal Peak.
 * Shop description:
 * You enjoy smacking about foes with that nail of yours, right? With this charm equipped, you'll be able to send them flying further with every hit!