To be clear, these are items that cannot drop at all unless a certain condition is met. Items whose drop rates are influenced by various conditions (aside from drop rate modifying effects or equipment) but whose drop rates are never zero are not conditional drops. This could have been considered a purely academic distinction until the advent of the Cat Burglar, who cannot steal most conditional drops but who can steal items with soft conditions.
Examples of Conditions
This is a non-exhaustive list of known drop conditions that exist for some items in the game. It is likely that there are additional conditions which are deliberately obscured or obfuscated to prevent over-farming or abuse.
Player Has Skill
A player must have learned a specific skill.
Player Is Correct Class
A player must be the right class for an item to drop. Usually such items have counterparts for each class.
Correct Inventory Contents
A player must have the correct number of an item in their inventory for the drop to occur; either a specific amount or a range of quantities (such as "more than zero").
- The gelatinous cube's drops are dependent on the player's inventory contents.
Number of Drops This Ascension
An item will only drop if the number of times this item, or another item, has dropped this ascension is a specific amount or within a range of quantities (such as "more than zero").
- Most quest items do not use this condition despite that they appear to. For example, the secret tropical island volcano lair map is a one-time drop because the monster which drops it can only be encountered once. Though the programming of KoL might technically designate such items as one-time drops, such a designation is irrelevant as it is not the true limiting factor on the item's drop rate.
- Some quest items operate this way, usually with a maximum incidence of one, when the monster which drops them can be encountered more than once. The broken wings are an example of this.
- The water-polo mitt is a one-time drop but is not a quest item.
- Lion oil will only drop if a bird rib has dropped at least once.
Player Has Completed Task
An item will only drop if the player has completed some specific task.
- All of the items unlocked by talking to Grandpa have this condition.
Item is Not Dropping With Other Item
There exist sets of items wherein each member has its own die roll but only one successful roll can trigger a drop in a given fight.
These conditions were used in the past but are no longer known to be used, sometimes due to changes to game mechanics.
Encounter is in Location
A monster or non-combat adventure which can be accessed in multiple locations must be encountered in a specific location to drop a given item.
- Gremlins used to drop Yossarian's tools only if fought in the correct location. The tools are no longer dropped by the monsters, but are generated when the molybdenum magnet is used at the correct time during fights.
- This condition used to apply to skeletal sommeliers and possessed wine racks before the May 14, 2014 Spookyraven Manor revamp.
Many items' drop rates depend on various conditions (other than drop rate modifying effects or equipment) but never have a drop rate of zero. They always can drop but the likelihood of doing so varies. These items are not considered conditional drops despite their drop behavior being influenced by similar criteria to those of true conditional drops.