As you probably know, Starcaft 2 Legacy of the Void has a prologue called Whispers of Oblivion that bridges the gap between it and Heart of the Swarm.
It also serves as a handy entry point for those of you who haven’t played Wings of Liberty of Heart of the Swarm, as well as a handy bridge between the two tales. It will feature the Dark Templar, Zeratul, who we haven’t really seen outside of cutscenes recently. It will eventually be available for free to everybody, you can get your mitts on it right now if you pre-order through Battle.net.
We’re expecting to get the full LoTV release this year, with a beta coming at some point this month for those of us that have pre-ordered.
I doubt any of you need to be told this, but Legacy of the Void is a standalone release, so you won’t need either of the previous SC2 games in order to play it. If you haven’t, though, I suggest you play it or at least familarise yourself with the story to truly appreciate the upcoming finale.