There is Fey monster called a Bogeyman...
1) Advance the Bogeyman to 25HD
2) Apply the Nightmare Lord template
3) Apply the Implacable Stalker template
Or, a Gingerbread Witch might be fitting... but getting kids to kill their families seems like an enchanter of sorts, focused on charms and compulsions. Possibly could make a Hoaxer Bard work, but Bughuul doesn't really give the kids any cursed tokens that I can remember.
An explanation, as if one is needed... it certainly wasn't asked for. Lol.
Advancing the Bogeyman to 25HD may sound like a lot, but it already is a 17HD creature. Even at 25HD, it only goes from CR 10 to CR 14-ish. You want 25HD, because the Fear Aura you get from the Implacable Stalker template affects creatures with at least 5 fewer HD than the Implacable Stalker... so, essentially everyone. Lol. You get to choose 4 feats with the additional HD, which can help make your monster more specific to your goals.
Those templates, though... that's where the magic happen with our Bogeyman. With the 25HD upgrade, and both templates, our Implacable Stalker Nightmare Lord Bogeyman is probably CR 18. The Bogeyman's existing Deepest Fear aura is upgraded from a 30-foot radius to 60-foot radius, and Implacable Stalker's Fear Aura upgrades the Shaken condition to Frightened. Nice. Plus you get legit Frightening Presence with a 30-foot radius on top of it. You also get a pretty significant ability score adjustment from said templates (Str+4, Dex+6, Con+6, Int+4, Cha+6), some fun feats, and a cubic buttload of goodies related to fear.
The Nightmare Lord's Dream Slave ability could, in fact, make children kill their families.