Back in wrath of the lich king, after killing yogg-saron, he will say "Your fate is sealed. The end of days is finally upon you and ALL who inhabit this miserable little seedling"
That last part was a little strange. Obviously he was talking about the planet, by why did he call it a seedling? It wasn't until many years later, in 2016 with the release of the chronicles book that players finally found out what Yogg-sarron meant. Azeroth, as we know it, is a titan egg of sorts. One day, the Planet of Azeroth would turn into a titan. And that's what the seedling refers to, the planet itself is kind of a seed growing a powerful creature. Well, maybe, there's a good case to be made that says Azeroth won't become a titan and is already dead due to all the old god influence.