Kacho
Member
They are randomly generated. But generally a legendary Deathclaw will only spawn where Deathclaws can spawn. Also you can clear an area out but monsters will spawn again after a set amount of time, hence no level cap.
The legendary gear also uses one of these random effects for weapon or armor.
http://www.nukahub.com/weapons/legendary/
http://www.nukahub.com/armors/legendary/
So you got to be lucky to get the random legendary effect on the exact weapon you want. The only none random legendary (called unique) gear mostly comes from quests.
http://www.nukahub.com/weapons/unique/
You are the best! Thanks for the info.
Also, this is a really awesome addition. Good job, Bethesda.