Chronic Expansion

Seekers of the Storm - DLC Content Chronic Expansion is part of the Seekers of the Storm DLC. It is only available if the DLC is enabled when starting a run. Click for more info.Chronic Expansion
Gain Damage after killing enemies in quick succession.
Every 5 enemies slain grants a damage counter bonus increasing the players damage by 10% (+5% per item stack), lasting as long as the player stays in combat.
Rarity	Common
Category	Damage OnKillEffect HalcyoniteShrine
Stats
Stat	Value	Stack	Add
Damage	10%	Linear	+5%

The Chronic Expansion is an item in Risk of Rain 2, introduced in the Seekers of the Storm DLC.

Every time the player kills 5 enemies, they gain an Seekers of the Storm - DLC Content
Increase Damage is part of the Seekers of the Storm DLC. It is only available if the DLC is enabled when starting a run.
Click for more info. Increase DamageSeekers of the Storm - DLC Content
This content is part of the Seekers of the Storm DLC. It is only available if the DLC is enabled when starting a run.
Click for more info.Increase Damage (Buff)
Gain additional damage.Gain +5% damage.
(stackable) stack, which increases damage by 6% (+5% per stack). This buff lasts for 5 seconds and is refreshed every time an enemy is killed.

Notes

• Correction: There are numerous issues with the item's description:
  • The actual damage boost formula is more complicated that the description implies. See the Math section for more details. A consequence of this is that the first stack increases damage by 6% not 10%.
  • The effect does not last while the player stays in combat, i.e., activating skills that disable Red WhipRed Whip
    Move fast out of combat.
    Leaving combat boosts your movement speed by 30% (+30% per stack).. Instead, each kill refreshes an internal timer to 5 seconds.
• Once the kill timer expires, one buff stack is removed every frame unless the player kills another enemy to refresh the timer.
  • The buffs are removed at a rate of 1 stack per frame. This is bound to the player's fps and not to the physics framerate which is 60 per second.
  • If the player pauses the game while the cooldown has not reached zero, the cooldown will freeze. However, if the cooldown has reached zero, the buff stacks will continue being removed every frame even if the game is paused.
• The item on the survivor's body has a digital display that updates whenever the player gains or loses a buff stack.
  • From the game's code it is implied the original intention was to display the values 000-999 and then just "GOD". However, due to a bug it always displays the current buff stacks with a preceeding 0, even if that value is greater than 999.
• The kill count is increased only if the killed entity is not a player.

Math

The formula that governs the damage boost is $buffStacks\times (buffStacks+5\times itemStacks)\times {\frac {baseDamageAtLevelOne}{100}}$.

As such the damage scales with the square of the buff stacks and linearly with the item stacks. It is also important to note that the damage boost is based on the character's base damage while ignoring their current level. This may be a bug.

Assuming the player kills 40 monsters, which is the monster cap, that would still only result to 8 buff stacks. Furthermore, the Director can take more than 5 seconds between spawning waves. It can be argued that if 3 enemies spawn in a wave, for example, the player could spread out the kills over 15 seconds, but realistically speaking it means the player will very rarely get to build up any meaningful number of stacks and maintain them for more than a few seconds.

On the other extreme, if the player has any combination of Fuel CellFuel Cell
Hold an additional equipment charge. Reduce equipment cooldown.
Hold an additional equipment charge (+1 per stack). Reduce equipment cooldown by 15% (+15% per stack)., Gesture of the DrownedGesture of the Drowned
Dramatically reduce Equipment cooldown... BUT it automatically activates.
Reduce Equipment cooldown by 50% (+15% per stack). Forces your Equipment to activate whenever it is off cooldown., and Soulbound CatalystSoulbound Catalyst
Kills reduce equipment cooldown.
Kills reduce equipment cooldown by 4s (+2s per stack). along with a Forgive Me Please45sForgive Me Please
Throw a cursed doll that repeatedly triggers your 'On Kill' effects.
Throw a cursed doll out that triggers any On-Kill effects you have every 1 second for 8 seconds., they can consistently register a kill at least once every 5 seconds, ensuring the buff stacks build up continuously. If the reduces the equipment's cooldown so that 3 Forgive Me Please dolls are active at any moment (that maximum that can exist), that translates to 36 buff stacks every minute. That would then result to 180, 216, 252, and 288 buff stacks after 5, 6, 7, and 8 minutes respectively.

The following table summarises the damage boost for various buff/item stack scenarios.

Buff Stacks	1 Item Stack	2 Item Stacks	3 Item Stacks	4 Item Stacks	5 Item Stacks	10 Item Stacks
1	6%	11%	16%	21%	26%	51%
2	14%	24%	34%	44%	54%	104%
3	24%	39%	54%	69%	84%	159%
4	36%	56%	76%	96%	116%	216%
5	50%	75%	100%	125%	150%	275%
180	33300%	34200%	35100%	36000%	36900%	41400%
216	47736%	48816%	49896%	50976%	52056%	57456%
252	64764%	66024%	67284%	68544%	69804%	76104%
288	84384%	85824%	87264%	88704%	90144%	97344%

It is important to remember that the above percentages only take into account the character's base damage at level 1. For example, for CommandoCommandoThe Commando is a jack-of-all-trades character that is reliable in all situations of the game.
Class: Ranged
HP: 110 (+33 per level)
Damage: 12 (+2.4 per level)
Armor: 0
Umbra: Cornered Gunslinger, who has a base damage of 12, 10 item stacks and 2 buff stacks would contribute $12\times 104\%=12.48$ additional damage, effectively doubling it. However, at level 11 Commando has a base damage of 36, so the Chronic Expansion boost of 12.48 is only a 33% increase.

On the other hand, when the buff stacks are self-maintained, the boost of Chronic Expansion vastly overshadows the survivor's base damage at any level and the effective damage increase can be thought of in terms of how many Shaped GlassShaped Glass
Double your damage... BUT halve your health.
Increase base damage by 100% (+100% per stack). Reduce maximum health by 50% (+50% per stack). stacks it'd take to achieve the same result. Continuing the example with a level 11 Commando and 10 item stacks but 180 buff stacks, it would result to a base damage of 5004, which is 139 times 36, or approximately the equivalent of 7 Shaped Glass.

Tips

• Due to the extreme binary nature of the item, if the player cannot consistently maintain the buff stacks, its effect will be triggered sporadically and briefly, similar to Berzerker's PauldronBerzerker's Pauldron
  Enter a frenzy after killing 4 enemies in quick succession.
  Killing 4 enemies within 1 second sends you into a frenzy for 6s (+4s per stack). Increases movement speed by 50% and attack speed by 100%., effectively only adding +5% damage per stack. In such a case the player benefits more by scrapping the item altogether and obtaining other damage-boosting items, such as Focus CrystalFocus Crystal
  Deal bonus damage to nearby enemies.
  Increase damage to enemies within 13m by 20% (+20% per stack)., Survivors of the Void - DLC Content
  Delicate Watch is part of the Survivors of the Void DLC. It is only available if the DLC is enabled when starting a run.
  Click for more info. Delicate WatchSurvivors of the Void - DLC Content
  This content is part of the Survivors of the Void DLC. It is only available if the DLC is enabled when starting a run.
  Click for more info.Delicate Watch
  Deal bonus damage. Breaks at low health.
  Increase damage by 20% (+20% per stack). Taking damage to below 25% health breaks this item., and Armor-Piercing RoundsArmor-Piercing Rounds
  Deal extra damage to bosses.
  Deal an additional 20% damage (+20% per stack) to bosses..
• The rocks on Sky MeadowSky Meadow (Stage 5)
  Sprite Fields
  You dream of serenity.
  
  can be a reliable area, albeit location-restricted, where one can rack up kills.

Lore

Shipping details
Order: Chronic Expansion
Estimated Delivery: 12/21/2057
Shipping method: Military/High Priority

Sent to:
General Reid
Hero’s Barracks,
Mars

Order details:
General Reid,
I examined the devices you sent me and sure enough your unit has been getting WAY too much phencyclidine in their doses. That may explain them trying to eat each other. I’ve lowered the threshold by 15%.

On the bright side, their hand eye coordination has been off the charts. Given the right gun, these soldiers could strike a jet from the ground.

If this trial goes well, and their lungs return to normal, I’ll clear them for duty.

- Dr. Zhao

Version History

Seekers of the Storm

• Added New Item: Chronic Expansion