How You Play Emperor :
▪4 mogu+echo of medivh+molten(40 dmg) ,without drakkari
▪4 mogu+ echo+ drakkari(40 dmg),when top deck drakkari after you play emperor or you dont have molten
▪4 mogu + molten+ echo(40dmg), when you top deck echo of medivh after you play emperor
▪4 mogu + 2 Molten +1 echo(60dmg) play it with emperor + drakkari

So in order to you to pull of the combo you must have 4 mogu ( {2 mogu + 2 simulacrum}or{2 mogu +1 simulacrum +1 molten reflection}), 1 emperor thaurissan , 1Drakari enchanter,and 1 echo of medivh in your hand