How many monstrous children did Loki have?

3 is correct. In Norse myth, Loki and the giantess Angrboda had three “monstrous” children: Fenrir the great wolf, Jormungandr the Midgard Serpent, and Hel, ruler of the dead. Fearing a prophecy about them, Odin and the gods tried to control their fates—binding Fenrir, casting Jormungandr into the sea, and sending Hel to Niflheim. These three shape Ragnarok: Fenrir kills Odin, Jormungandr battles Thor, and Hel commands the dead. Memory tip: think “F-J-H”—Fenrir, Jormungandr, Hel—or “Wolf, Worm, and World of the dead”: one wolf, one serpent, one sovereign of the underworld.