Okay, not exactly Deckard Cain, but there is an achievement in his honor. Click the image to see the full-sized shot. Details below, courtesy of our partner MedievalDragon, who selflessly stayed up all night playing the single player missions and finished them (on normal) by early evening of the 28th. Purely so he could report on the cool info for the rest of us!
This achievement is after you finish the Gates of Hell mission in planet Char. There’s a cinematic right after, then you see an interactive Raynor, General Waterfield and Tychus with a char background. The achievement suddenly pops when that loads. It’s interactive as in you hover the mouse over Raynor, the General and Tychus, and they become silhouette-highlighted, you click them and they have a cutscene-dialogue.
MD also let me know how the game ends. Horrible spoiler alert! The ending is… a cliffhanger, setting up events to be continued in the expansion pack. I know, I was shocked and amazed by that as well.