Mutation
This is about the mechanic in the mainline series. For the features in the puzzle series, see Monster Mixing or evolution. For the concept seen in the Dragon family, see regeneration.
Mutation is a game mechanic introduced in What Did I Do to Deserve This, My Lord!? 2. It involves having monsters adapt through stresses introduced through the threat of extinction, such as overpredation, being killed by heroes, starvation, and other means. This leads to the creation of Basic Breeds, Abnormal Breeds, Giant Breeds, and Rare Breeds. Managing mutation effectively can lead to "free" upgrades to Badman's army. Dragons cannot mutate.
Conditions
The conditions for mutation are simple: in a set period of time, a large amount of a given class of monster must perish, and the ratio of monsters must be sufficient. For example, Liliths require a 20%+ ratio, so for mutation to take place, there must be four others present in the dungeon.
In the event of high stress, Pure Breeds of the monster in question will begin to spawn, which are often a hinderance to one's army. For example, if a Lizard Knight is stressed, it will spawn a Pure Lizardman. Thus, when aiming for mutation, it should be completed as quickly as possible to minimize the "duds" spawned in the process.
If the conditions for mutation are met, the game will tell you that a monster is looking "ominous", in which the game will attempt to spawn the result as soon as possible. However, there are times where it will occur without warning, which can be inconvenient if the player has a plan. Once a monster reaches its maximum level, mutation remains possible: instead of going to a higher one, it will return to the lowest instead. For example, in No Heroes Allowed!, a Lizard Lord can become any of a Lizardman, Siesta Lizard, Obese Lizardman, or Frill Lizard. To alleviate this, it is possible to reset stress levels through using Dungeonquake, keeping them at their highest level. This can also be useful for keeping Level 4 breeds in No Heroes Allowed!, which have higher defensive stats and thus may be more appropriate for a given situation.
Gallery
Almanac infographic for mutation in What Did I Do to Deserve This, My Lord!? 2
Almanac infographic for mutation in No Heroes Allowed!
