Arthas Menethil is serious business. Actually, wait, he's a sadistic fuckhole who tries to kill everything he once liked (except Jaina).
Arthas used to be a boy, and used to play with dirty peasants,
train with get owned by his dwarf teacher Muradin. He also had a horse named Invicible. Eventually, he got too attached, and went on a joyride like any self-respecting teenager. How did that end up?
Just like that.
Then he grew up, got a hammer, and stole some elf's girlfriend. Did I mention you get to play as said elf? And later fight him? No? Well, now I just ruined half the expansion for you. Grow a pair.
Arthas, after leveling up on some orcs who don't believe in serious business, goes north. After killing a necromancer who tells them Mal'ganis is the guy who created the Undead (spoiler: not even close), Arthas loses his nerve and instructs his men to kill off everyone in the city of Stratholme (although it did have a few zombies). He gives them a speech about how it's not a glorious battle they're about to fight, rather, it's ugly, necessary, serious business.
Serious business happened here.
He then goes to the North Pole, where he finds his old friend Muradin. They proceed to kill their own boats (and then the mercenaries that helped them), and go farther north.
Eventually the two get to a sword called Frostmourne. Muradin realizes it's cursed, but Arthas just flips him off and takes it. Everybody (including Muradin) thinks Muradin died from the ice explosion, but really he just got amnesia and returns in World of Warcraft. Arthas goes to kill Mal'Ganis with his new runeblade, while the dreadlord tells him it's not Santa Claus who lives at the North Pole, it's actually some guy called the Lich King.
And then Arthas kills his father.
Like the new sword I got from
Santa the Lich King? It's going through your neck.
This campaign is broken into 3 kinds of missions:
Europe Missions: Someone has something that you want, so you kill the shit out of them. (Missions 2, 4, 5, 6, 7)
Satan Missions: You summon stuff. (Missions 1, 8)
Destroy Missions: Really? Only one where the objective is just "Destroy the base"? What kind of RTS is this?
Basically everything you were protecting back in the Human Campaign, you get to kill. You still hate the orcs by the way. If you didn't think you got enough time to kill them in Human mission 2, you now get to have a do-over. They even have the same fucking name.
This campaign is serious business because instead of leveling up, you level down. Happy hunting!
So, in this campaign, you:
Uh, yeah. In World of Warcraft, characters like Illidan, Kael, and Arthas, who got so much time put in trying to make a unique personality for each one, get killed off because that's how the game works: Level up, kill the shit out of famous characters.
It's Grand Theft Auto World of Warcraft, pretty much.