User blog comment:Alica123/Misadventures In Wikia Hell: The Legend Of Doranor/@comment-4257094-20120318160144/@comment-4257094-20120318190019

Here's what it's about: "Set in contemporary New York City, a seemingly ordinary teenager Clary Fray, discovers she is the descendant of a line of Shadowhunters, a secret cadre of warriors dedicated to driving demons out of our world. When Clary's mother disappears, she must join a daring group of young Shadowhunters (half human/half angel) on an adventure, which leads her through a city filled with mischievous fairies, eccentric warlocks, werewolf gangs and other strange creatures." (Just realized there's even a [shadowhunters.wikia.com|wiki] for it o.o)

I think the whole demon villian / shocking twist about the demon's children calls that series to mind.