So here's a surprise, Thrall's mom is alive! Sort of...orrrrr undead? We'll know for sure when Shadowlands will be released. Anywho, the main character of the 2nd Shadowlands Afterlives animated series is Thrall's mother, Draka, who's in service of one of the 5 houses of Maldraxxus, the military ward of the Shadowlands. In her previous life (let's just say she is still alive) she died while protecting Thrall, when he was a baby, during the Orc civil wars. Now apparently Maldraxxus is important to the Shadowlands, because in the animated short Draka's master mentions that if Maldraxxus falls, so will the rest of the Shadowlands. This means that the 5 houses are apparently pretty important and she plays a role in it.
So, go and watch the animated short for the rest of Draka's backstory. If you missed the first short, Bastion, you can view it here. And if you want to know more, you don't have to wait long. Shadowlands will be release October 26th 2020 and is already available for (digital) pre-pruchase at Blizzard's website.