The Opening of the Dark Portal

The moment when, game-wise, all started, when the orcs came into Azeroth and destroyed Stormwind, prompting the human kingdoms to create the alliance and eventually led to the Second War, you decide that's the perfect moment to go, but when and as who, you could just appear as yourself and see how everything goes down, or take the role of some already established character, you could become Medivh and not open the Portal in a first place or take the place of Gul'Dan or other orc and lead the Horde, or just plainly create an Orc Clan or Human kingdom to lead for yourself and do whatever the hell you please (Even though you already can do that, but it would be more fun if you had to earn it).