Monster only in darkness???

[Chilton]

Thats actually quite a tricky one - I dont think light is measured that way, but what you could do is make some kind of script to spawn an enemy if you leave a lit area, and/or if you turn your lantern off, and unspawn it if you either re-enter a lit area or turn your lantern on...?

Dear me, that would be a hard script... Maybe?
Hmm
*Starts pondering pseudo-code*