Game Rules
Game rule replaces config files.
maximumTrainerCountPerPlayer
Defines the number of trainers spawn around a player.
trainerSpawnIntervalInSeconds
Defines trainer spawn interval in seconds.
doTrainerApplyStatusCondition
Trainers retaliate when attacked by players. When a player get hit by trainers, one of the player's Pokémon will receive random status condition.
Example
/gamerule maximumTrainerCountPerPlayer 1
/gamerule trainerSpawnIntervalInSeconds 60
/gamerule doTrainerApplyStatusCondition true