animary wrote: ... Make them easier to create, not invincible but they respawn a day or so after being destroyed. ...
Considering that for some, killing in a haven is such a mundane process that it can be compared to tax evasion (and nightbanes are weak as toddlers), an analogy of the proposed method transferred to real life immediately appeared in my head:
Imagine being %billionaire name%, starting your day by killing dozens of babies who are patiently waiting for you to wake up. And you do it literally every day. Funny isn't it?