Kills per Level (abbreviated KPL) is a concept in ADOM related to monster generation. It can be used to predict the level of generated monsters. In newer versions of ADOM, the influence of KPL has been greatly reduced.
KPL is theorized to work the following way: if a specific monster has KPL of X (positive integer value), then RNG will generate this monster at level 1 until PC has killed X monsters of this type. As soon as this number of kills is reached all subsequent monsters will be generated at level 2. As soon as X * 2 number of kills is reached monster starting level will increase to 3. This linear progression will persist throughout the game. Monsters generated in high DL areas may be generated at a higher level than KPL would indicate.
KPL defines how fast monsters become more powerful as PC kills more of their kind. Lower KPL values mean faster increase, while higher KPL values allow less cautious monster handling. Note that different monsters progress their basic stats (DV, PV, hit points and damage output) with different rates as they level up, so KPL should not be considered a universal measure to predict enemy difficulty.
In practice, PC progresses much faster than monsters and has access to equipment which makes KPL consideration more or less redundant. There are several exceptions which are mainly attributed to KPL design flaws. These exceptions include:
- Large spiders, Giant spiders, Cave fishers and Tarantulas
- Battle bunnies
- All worms
- Wolfs, Dire wolves
- Chaos servants and Greater chaos servants
Aforementioned monsters all possess relatively low KPL values and can breed/be summoned which leads to so-called uberjackal effect when they start to possess significant danger to PC.
Note that this was toned down in 1.2.0 . KPL is now determined by the formula KPL = rarity*10 (minimum 20), with rarity being a number ranging from 0 to 150. For the previously problematic monsters, the KPLs are now between 100 and 1000 (with the exception of battle bunnies at 20). As a result, KPL does not have much relevance for later versions of the game.
Even in later versions, some monsters that are generated in great numbers can still become noticeably more powerful due to this effect if the player kills enough of them. If you make a habit of hacking your way through the Animated Forest, you might find it becomes more difficult with time, not less, with the Animated trees suddenly hitting dangerously hard. Something similar can happen when farming fungoids for mushrooms by the pool on the last level of the Fungal Caves.
There are several exceptional situations that cause different monster generation scenarios. These include:
- Small Cave monsters are generated with increased level based on PC level
- Molochs and Greater molochs, as well as Necromancer's slaves adjust in power when in PC line of sight, which increases their level to match PC's
- Ultimate doppelgangers do not adjust in power, but have DV, PV, and speed equal to the PC's