The preview reveals that when Garona (who has the same tailor as Valeera Sanguinar apparently) killed King Llane, she was actually pregnant. When she 'disappeared' from the overall Warcraft story, she handed off her child to the Undead Mage/Warlock/Necromancer Meryl for safekeeping since she couldn't trust herself while she went to deal with her inner demons. It's interesting to note that this Undead Necromancer isn't actually a member of the Forsaken, so that Forsaken Warlock action figure you may have purchased awhile back isn't a Forsaken at all. He predates Ner'zhul by quite a bit, and the comic describes him as being undead via his own will and sorcery. He should prove to be a pretty neat character.