Focus
Focus is a Spell in Hollow Knight. It allows the Knight to heal using SOUL.
Function
Hold down FOCUS/CAST to drain SOUL and regenerate health at a rate of 1 Mask per 33 SOUL. It takes 1.141 seconds to heal the first Mask including the initial startup time of 0.25 seconds.
Continuing to hold FOCUS/CAST continues to heal 1 Mask of health as long as the Knight has 33 or more SOUL. This takes 0.891 seconds and skips the startup time.
If the Knight does not have enough SOUL, it is not possible to use Focus. However, if Focus is used while at full health, or a full cast of Focus is not performed, stored SOUL is still used up. Getting hit by an enemy interrupts casting (even while protected by the Baldur Shell Charm or having the damage negated by the 
Carefree Melody Charm) and wastes any SOUL used during the incomplete cast.
Modifiers
Several Charms change the way Focus works:
- Baldur Shell gives protection while Focusing.
- Deep Focus heals 2 Masks of health per Focus at a 65% slower rate.
- Quick Focus allows the Knight to Focus 33% faster.
- Equipping both Quick Focus and Deep Focus restores 2 Masks at a 10% slower rate compared to having neither equipped.
- Joni's Blessing turns all Masks into Lifeblood Masks, preventing the Knight from healing Masks when Focusing.
- Shape of Unn allows the Knight to move while Focusing.
- Spore Shroom creates a cloud of damaging spores after Focusing.
How to Acquire
The Knight starts the game with this ability. Additionally, there is a tutorial prompt that appears after the Knight passes the Focus Lore Tablet in King's Pass and has enough SOUL to heal a missing Mask.
Trivia
- A Lore Tablet in King's Pass states the following:
- "Higher beings, these words are for you alone.
Your great strength marks you amongst us. Focus your soul and you shall achieve feats of which others can only dream."