Health

 is an attribute present on all Survivors and monsters in Risk of Rain 2. Taking damage reduces the player or monster's health. When a character's health reaches 0 or less, they die, granting Gold and experience points to the killer (if the character was a monster) in addition to activating any on-kill effects. Any killed Survivors are revived upon entering a new level. If all Survivors in the current run are dead, the run ends, and a statistics screen appears. and causes the holder to return to life upon death, restoring them to full health and making them  for 3 seconds.

Various effects are calculated as a proportion of the character's max health or max health and shields, which will be referred to as maxHP and fullCombinedHealth for the remainder of the article.

Keep in mind that all the stat values below are internally stored are floats, but are rounded up to the nearest integer when displayed on the screen. For example, with 1 stack of  actually heals for 0.6 health, but displays 1 and the rapid fire rate may create the illusion it heals for more.

Health
The base health value is calculated from the following contributions:
 * $$baseHealth + levelHealth \times levelsMinusOne$$
 * +infusionBonus if the character holds at least one stack of.
 * +25 per stack of.
 * +40 per stack of.

A modifier with a starting value of 1.0 is then built by considering the following:
 * BoostHp, which gives +0.1 per stack.
 * and, each giving +0.1 per stack.
 * Having the affix gives +0.5.
 * , which gives +1 per stack.

The final health value is then computed by multiplying the following:
 * base health value
 * modifier
 * $$1 / (1 + cutHpStacks)$$, which is the item given to all monsters while the is active, effectively halving their health.
 * 10, if the character is an.
 * The accumulated value so far will be referred to as beforePerfectedMaxHP.
 * If the character has the affix, the health is set 1.
 * The accumulated value so far will be referred to as beforeOverloadingMaxHP. If the condition has not been satisfied, we simply have beforeOverloadingMaxHP = beforePerfectedMaxHP.
 * If the character has the affix, the health is halved. Holding both the Perfected and Overloading affixes effectively sets the health to 0.5.
 * The accumulated value so far will be referred to as tempMaxHP. If the condition has not been satisfied, we simply have tempMaxHP = beforeOverloadingMaxHP.
 * 1.5 if the character has the active.
 * $$1 / cursePenalty$$

Shield
Shields work similarly to health, and appear as a blue (magenta if holding ) segment in the player's health bar. As characters suffer from damage, shields are emptied before health. Lost shields replenish over 2 seconds after the player takes no damage for 7 seconds. As a result, players must avoid damage for 9 consecutive seconds to fully regenerate their shields. Shield regeneration is separate from healing, so any modifiers to healing or effects that activate from healing will not apply to regenerating shields.

Note: Gaining shields will not increase healing that restores a percentage of maxHP. Therefore, these items' healing is not affected by any shields the player has:, , , , , , (both the passive and active component), , and.

Shields will also not affect the damage from the, the amount of health converted to additional shield by , or the amount of fall damage taken, as all of these also depend on maxHP.

However, fullCombinedHealth is treated as health for the purposes of, , , , , , , , barrier gain and limit from all sources (, , and ), skills, one-shot protection, and the damage from the.

Shield is indirectly influenced by, , , and since these effects depend on fullCombinedHealth.

The is a unique case, as it grants shields based on the user's actual maximum health, ignoring. This means the Personal Shield Generator does not benefit from the health bonus Transcendence applies to health-providing items; however, neither does it suffer from Transcendence's health reduction. The Personal Shield Generator still benefits from the increased maximum health of normally.

The shield value is computed by adding the following contributions:
 * $$0.08 \times shieldGeneratorStacks \times tempMaxHP$$
 * 0.1 for each stack of
 * $$beforePerfectedMaxHP \times (1.5 + (transcendenceStacks - 1) \times 0.25)$$ if the character holds  or has the  affix. Note that effectively 1 stack of Transcendence gives a scaling factor of 1.5, while the Perfected affix only 1.25.
 * $$0.5 \times beforeOverloadingMaxHP$$ if the character has the affix.

This value is then multiplied by the following factors:
 * 1.5 if the character has the active.
 * $$1 / cursePenalty$$

Barrier
Barrier is displayed as a yellow, semi-transparent overlay over the health gauge. The maximum amount of barrier a character can have is equal to fullCombinedHealth, and it depletes rapidly at a rate of $$maxBarrier / 30$$ per second. In the absence of any shields, this is effectively 3.33% of the character's maximum health per second. When taking damage, the barrier is depleted before shields.

Barrier can be used to circumvent the negative effect of, as it can double the player's halved max health temporarily.

Curse
Curse is an internal attribute that lowers maximum health. Curse prevents the player's health from healing back to full and is capable of disabling One-Shot Protection (OSP) if Curse is equal to or greater than 10% of maximum health. The portion of health removed by Curse appears as a hollow, partially shattered segment of the player's health bar.

The curse modifier reduces the health and shield stats by dividing them, effectively having a hyperbolic effect. The modifier starts with a base value of 1.0 and the following contributions increase it accordingly:
 * $$\times 2^{stacks}$$, for any stacks.
 * $$\times 10$$, if the is active.
 * $$+0.01 \times stacks$$, for any buff stacks.
 * $$+0.1 \times stacks$$, for any stacks.

Health Regeneration
All Survivors and some monsters regenerate health passively.

The regen stat relies on a regen factor for its calculation, $$regenFactor = 1 + 0.2 \times levelsMinusOne$$. A temporary value is then build up by summing the following contributions:
 * $$baseRegen + levelRegen \times levelsMinusOne$$
 * $$1.6 \times stacks \times regenFactor$$, for.
 * $$3 \times stacks \times regenFactor$$, for if the character is out of danger (not taking damage for 7 seconds).
 * $$0.1 \times stacks \times regenFactor$$, for.

The regen stat is then calculated with:
 * $$temporaryValue \times difficultyModifier$$, which is the difficulty regeneration modifier (Drizzle=1.5, Rainstorm=1, Monsoon=0.6).
 * If the character is afflicted by or, set the previous value to 0. This means that the  who has negative regeneration will not lose any health while on fire, assuming she can mitigate the burn damage.
 * If Acrid's buff is active, add $$0.1 * tempMaxHP$$ to the previous value. This means  is unique in that he can still have some regeneration while on fire.
 * If the character has the affix, set the previous value to $$max(0, previousValue)$$. This means the Heretic will not lose any health.
 * If the charater has any HealthDecay stacks, adjust the previous value according to $$min(0, previousValue) - tempMaxHP / cursePenalty \times stacks$$.
 * If the character has the active, multiply the previous value by 4.
 * Else if the character has any, multiply it by $$0.95^{stacks}$$.

Healing
The healing procedure is triggered every frame for $$regen / 60$$ amount, or whenever the character receives any healing, be it from proc effects such as, active items such as , or other sources such as.

The procedure goes through the following steps:
 * If the character is, exit immediately.
 * If the character has, multiply the amount by $$1 + stacks$$.
 * If the character is a player and the difficulty is Eclipse 5 or higher, halve the amount.
 * If the character has, set the reserve to $$min(reserve + (amount \times (1 + stacks)), maxHP)$$ and exit immediately. The healing procedure will be called at the appropriate intervals to apply the healing from the reserve, which means that Rejuvenation Rack and the Eclipse 5 modifier double dip their effects for this item.
 * Increase the health by amount up to maxHealh.
 * If the character has, there is any leftover amount, and it is not passive regeneration, increase barrier by $$remainingAmount \times 0.5 \times stacks$$.
 * If the healing is not passive regeneration, modify the healing pool to $$min(pool + amount * stacks, fullCombinedHealth)$$.

Version History

 * Anniversary Update
 * Gameplay Changes
 * Low Health Threshold
 * 20% ⇒ 25%
 * PC Patch v1.0.1.1 (Build ID No.5440050)
 * Bug Fixes
 * Healing numbers are properly green
 * Early Access Artifacts Content Update
 * Quality of Life
 * Add a new death visual effect for players so it’s clearer when they die
 * 🌧 Update Game End Report to use special strings and icon if no killer is found
 * Change "Killed by" text to be right-aligned so it can fit longer names
 * Early Access Hidden Realms Content Update
 * Gameplay Changes
 * Update regens to not be multipliers, but scaling flat bonuses to decouple benefits of regen items from base regen
 * The result of this is that all characters regardless of their baseline regeneration all benefit the same from regen items. This will only affect melee characters WITH regen items - nobody else is affected.
 * PC Early Access Patch (Build ID No.4233443)
 * Gameplay Changes
 * Health Regeneration
 * Increase Player's Health Regeneration by +66% in difficulty.
 * Increase Drone Health Regeneration by +150% in ALL difficulties
 * All these regeneration changes have been highly confusing and affecting difficulty too drastically – as a summary, and  are the same as Skills 2.0 Release, while  is now a bit easier.
 * Early Access 'Skills 2.0' Content Update
 * Bug Fixes
 * 🌧︎Replace instances of unknown deaths (pots, out-of-bounds, etc) having a white box and a blank entry with a generic “mystery” attacker
 * Early Access Scorched Acres Content Update
 * Gameplay Changes
 * Add support for new health-type: Barrier
 * Barrier is a health value that can exceed your maximum health, but degrades over time.
 * Add new stat: Curse
 * Curse is the old Shaped Glass functionality, which locks away a portion of your healthbar - it has been moved over to a generic stat so we can use it for other items in the future.
 * Disable Base Health Regeneration if on
 * QOL
 * ☂ Player healthbars now flash when at low health
 * Early Access Patch (Build ID No.3830295)
 * Bug Fixes
 * Losing max shields now properly removes extra shield
 * Early Access Patch (Build ID No.3731106)
 * Bug Fixes
 * [Community Found] Allow changes in maximum health/shield to instantly fill that missing amount. This means that /  will no longer give you empty shield.