57 Leaf Clover

The 57 Leaf Clover is an item in Risk of Rain 2.

The Clover makes random beneficial effects more likely to occur for the holder, and as such is the counterpart to the (which makes beneficial effects less likely to occur). It affects all random effects except.

If a successful proc is not achieved on a roll, it will be rolled one additional time per Clover. For example, assume the player has one item that has a 20% chance to proc a beneficial effect on-hit, and has one 57 Leaf Clover. If the player attacks, and the item does not activate, the roll will be done once more, as the player has one Clover.

Successes are measured per effect, not as a whole. If one item roll is successful, other items that were triggered by the same proc will continue to roll if unsuccessful.

Since items from chests are created based on the world seed, the Clover does not affect them.

Math
In order to calculate proc probability with a certain number of Clovers, the following equation can be used:

Where:
 * p = total item proc chance (between 0 and 1)
 * x = the number of Clovers in the player's inventory.
 * y = new item proc chance (between 0 and 1) with x amount of Clovers.

The inverse of the equation, to find the number of Clovers required to achieve a certain proc probability, is:

Note that this is a logarithmic equation. As such, it is impossible to achieve 100% proc chance on an effect (regardless of the number of Clovers held), unless the base chance is already 100%.

In order to calculate proc probability with a certain number of Clovers and a certain number of times a proc chance is rolled, the following equation can be used:

Where: This equation is useful for calculating logbook drop chances for multi-phase bosses, like and, or more uncommon enemies, like.
 * p = total proc chance (between 0 and 1)
 * x = the number of Clovers in the player's inventory.
 * t = the amount of times a proc chance is rolled.
 * y = new proc chance (between 0 and 1) with x amount of Clovers and t amount of times the proc chance is rolled.

Interaction with Purity
In the game code, the number of Clovers is referred to as "Luck," with each Clover giving +1 Luck. There are no other means of acquiring positive Luck. Negative Luck is also supported, and can be obtained via the lunar item. Positive and negative Luck will cancel each other out, and thus an equal number of Clovers and Purity will equate to 0 Luck.

The game runs a proc chance  times, where Luck is the total amount after Clovers (positive) & Purities (negative) are applied.

If the player has 7 Clovers and 5 Purity, the 5 Purity will cancel out 5 of the Clovers, resulting in a net +2 Luck. This means any given proc chance will be rolled two additional times for a positive outcome. If the amount of each item is switched, resulting in -2 Luck, the proc chance will be rolled two additional times for a negative outcome; this can also be seen as the proc chance needing to successfully roll three times for it to proc (once for the initial roll and two more for each negative Luck).

Exhaustive List of Clover Effects
Luck does not affect chest spawns or contents, Shrine of Chance outcomes, the chance for an to drop, or the chance for monsters to drop items with the  enabled.

Survivor Effects

 * Critical strike chance. Survivors have a base 1.0% critical strike chance.
 * chance to with  (50% base chance).
 * chance to inflict on hit (base chance is equal to the proc coefficient of the damage).

Item Effects

 * chance to critical hit.
 * chance to stun a target.
 * chance to a target.
 * chance to fire chain lightning.
 * chance to attach a sticky bomb.
 * chance to fire a missile.
 * chance to drop an ammo pack.
 * chance to drop a gold nugget.
 * chance to hook enemies.
 * chance to spawn a ghost.
 * chance to fire magma balls.
 * chance to summon a lightning bolt.
 * chance to gain gold.
 * chance to get a . A single Clover reduces the chance from 20% to 4%.
 * chance to instantly kill.
 * chance to barrage an enemy with lightning.
 * chance to root.

Gameplay Effects

 * Monster log drop chance.
 * Elite equipment drop chance.

Monster Effects

 * If a monster acquires critical strike chance, this chance is affected by any Clovers it has. Monsters have 0% base critical strike chance.

Version History

 * Anniversary Update
 * Major Content
 * Added New Lore Entry:

Trivia

 * The 57 Leaf Clover is the successor to the 56 Leaf Clover from the first Risk of Rain. The 56 Leaf Clover did not interact with chance effects, but instead gave a chance for Elite monsters to drop random items upon defeat.
 * This behavior is partially carried over to Risk of Rain 2, as the 57 Leaf Clover affects the chance for Elite monsters to drop their Elite equipment.
 * Before the Artifacts update, the unreleased code for the would check for the Luck of the killer. This is no longer the case.
 * Before the full release of Risk of Rain 2, and  were affected by the Luck stat, and therefore were more likely to proc when the player had a Clover. This is no longer the case, as the 1.0 update revamped both Bands.
 * An interesting leftover of this design change is that Kjaro and Runald, the two who spawn with the Bands in the, also both spawn with 20 stacks of 57 Leaf Clovers.