When Nephilim, demons or warlocks put up glamours, it is so that mundanes cannot see them; the mundanes see either something they would understand or nothing at all. These glamours can be put down willingly, though.
Mundanes can be be infected with what are considered to be demon diseases: lycanthropy and vampirism; they can be turned into werewolves when bitten, and vampires or servants when fed blood. They can also become Forsaken when runes are Marked or applied on their skins. They can use and perform magic by practicing witchcraft; those who successfully practice magic are referred to as "witches". They can also be turned into Shadowhunters through Ascension with Mortal Cup.
When Shadowhunters have children with mundanes, the children will be Shadowhunters since their angelic blood is dominant. Sometimes, demons may disguise themselves as humans and seduce mundane women which will make her pregnant with a warlock child.
- "Mundane" means ordinary, common, or banal.
- Cassandra Clare used this term to refer to regular humans in the series because her gamer friends called people who don't play Dungeons & Dragons "mundane."