Shadow Demon Slaughterhouse

*Once the meta shifts so that Blademaster Samuro isn't on every team, (or if you are dodging those teams more than I am haha) you can switch Mannoroth out for Vol'jin for more shadow synergy, in which case you would lead Jaraxxus, Rathorian, Tamsin

The idea is to spawn as many tokens as possible to build up Diablo's health and Sylvanas' reclaimed souls.

Turn 1, you lead with the trio of demons, and they do demon things, while trying to burst down Samuro since Fel Lash and Legion Burst can both go through taunt, although that combo only does 60 damage so maybe dropping Rathorian for something else that can get through taunt on turn 1 is worth it to you if you really want to shut that overused comp down (although watching them tilt when the random damage from Rathorian kills Samuro is pretty funny too) Regardless though, you have no blue so none of your mercs will die turn one, then the fun begins. 

Turn 2, summon Hulking Overfiend, Howl of Terror/Fel Lash and Fist of Jaraxxus 4 times. I chose to run Jaraxxus' more fist damage rather than removing the RNG, but both options are good

Switch back and forth until someone goes down, switch in Tamsin. She summons her demon, more demon things, then eventually you should be in a position where Diablo and Sylvanas can clean up 

This is only theorycraft because I don't have Diablo, but the rest of the comp is solid even when just built around Sylvanas (and you run vol'jin instead)