Adjust evolution rates for killed monsters
While pondering random monster distributions I stumbled upon a problem in the code: the evolution level of a monster (kind of bonus adjustment to make monsters more dangerous if many of them had been killed) was dependent on the rarity of the monster - rarer monsters evolved faster. But as rarity depended on the level of the PC there were actual jumping points when monsters just doubled in evolutionary dangerousness. This dynamic factor has to be replaced by the static base rarity of a monster.