5.3/5.4 Siege of Orgrimmar? (Kor'kron Guards attack us in 5.3 PTR build)

One of the guards dropped this

You can see General Nazgrim :3

It's not a scenario they just started to attack us. In the barrens there are also these camps full of goblins and orcs and a mini boss (16mil hp)

Lore-wise, while most of the Horde don't particularly like the Alliance, they are appalled at Garrosh's actions. He has divided the Horde with a racist Orc-first policy, repeatedly antagonized the powerful Alliance, and spit in the face of other Horde leaders. The Tauren and Trolls see shadows of Gul'dan's betrayal to the Burning Legion in the Warchief's pursuit of the Sha.

• Jaina has also been the voice of peace and reason in the conflict, and a moderating influence on a very hot-headed Varian:
• Jaina intervened in Icecrown Citadel, and convinced Varian to allow Varok Saurfang to recover his son's body.
• Before this, in the wake of the Wrathgate, she stopped Varian from burning what was left of Lordaeon to ash.
• Jaina was also a personal friend of Thrall?

Beyond Jaina, the wars with the Burning Legion in Outland, Deathwing's Cataclysm, the threat of Arthas, and the resurgent Old Gods in Kalimdor and Northrend are very fresh (<10 years). The leaders of both factions seem conscious of the threat of complete and utter annihilation of all life on Azeroth if open, total war occurs, although this hasn't prevented the two sides sniping against the other in the knowledge that there won't be a massive response.

• The Undead of Lordaeron are the fathers, sons, and siblings of citizens and soliders of modern-day Stormwind. The leadership of Stormwind see the eradication of the Forsaken as being nothing more than putting the dishonoured dead to their rest.
• Women and children were cold-bloodedly butchered in Ashenvale for the sake of wood.
• Southshore was bombed to the ground by Sylvanas.
• Gilneas was invaded and sacked by the Forsaken, with Garrosh's sanction.
• Theramore was reduced to a hole in the ground.

In recent weeks (in lore), Garrosh has pissed on the neutrality of the powerful Kirin Tor and Dalaran, has tried to harness the Sha/Old Gods to corrupt his own people, instigated the attempted murder of the revered Vol'Jin, and almost killed the son and heir of Stormwind's king.

Fear, and power. There are immensely powerful arcane casters within each faction. By her own tacit admission, Jaina could slaughter every man, woman, and child in Durotar (during the purge of Dalaran) in minutes. And in the end, Varian has to restrain her. What does that tell you?

Look at me. I am a champion of the Alliance, and the hero of the Exodar. At level 90, I am a demi-god, a Draenei with powers beyond the ken of an ordinary person - and by the lore, I am utterly loyal to the Lion of Stormwind alone. I could single-handedly lay waste to whole towns.

The two factions are Cold War-era America and Russia. They are vast, and globe-encompassing powers that possess strategic nuclear weapons. If total war happens, there will be no winner. No survivor.