Diablo (character) as Starcraft 2 Easter Egg in Sc2 singleplayer It appears it looks like the diablo from Diablo 3.
There is a mission in Starcraft 2 singleplayer called “The Devil’s Playground” where you will play “Diablo” himself in a diablo like theme. This is the only like Diablo theme mission in starcraft 2. There is craters, vulcans, and lava in the mission. Also you will get an achievement for completing it. Goodluck.
Watch the picture below.