I'm of the belief that we merely destroy the Old Gods' corporeal forms when we "killed" them. Whenever we defeat them, they always say some sort of "I'll be back, it's only a matter of time."
This is further supported by what we've seen from each of them. They each get stronger over time. The Titans though C'thun dead - he came back and nearly destroyed the world. Yogg-saron was chained up - be broke free and corrupted nearly all of his jailers. Hell, Y'shaarj was thought completely dead and he's still whispering.
It seems evident that they continually (albeit slowly) gain strength over time. Again, C'thun's and Yogg-saron's resurgences and Y'shaarj's continual whispering seem to support this.
It's only a matter of time until they come back. We've merely put off the problem.
It was clarified by a CDev a while back.
Old Gods are outside the cycle of life and time. When you see them, as in when we saw Yogg in Ulduar, they aren't really there. Sure, there is a physical body present that is controlled by Yogg-Saron, but it isn't his corporeal form. It's unknown even Old Gods even have one.
They literally sit in their own realm where they cannot die, and where time is nothing to them. So when we defeated C'Thun and Yogg, all we did was push them out of the physical realm.
The only way to completely destroy an Old God is to remove it completely from existence and time. There is no known way to do that which we have been told.
We destroy the shell and send the part of their spirit, for lack of a better word, back to the whole.
I tend to think of it like the KJ fight in Sunwell. He's trying to gain access to Azeroth but we push him back to where he came from. That's basically all we're doing with the Old Gods.
tauren/trolls/elves/undead (maybe) would be fine as they are naturally made of flesh
orcs/draenei would also be fine as they arent even from a planet that was ruled by old gods
this is all assuming the death of an Old God undoes or destroys everything they've influenced
The Old Gods remind me of Dark Force from the Phantasy Star Games. You can never completely destroy it because to do so would result in the instant destruction of whatever planet it's on. All you can do is subue it and seal it for 1000 years.
Basically if one wanted to be rid of the Old Gods for good you'd have completely evacuate the entire planet and let the Titans nuke it. The remains of Draenor in The Twisted Nether could be a viable option to evac the entire planet.
Iron Vrykul are a variant of vrykul composed of iron. Like the iron dwarves and iron giants, they are servants of Loken.
The names of some trash mobs hint that some of them are made of hardened steel and titanium, but it seems they are still part of the 'armies of iron'.
The only apparent creator of iron vrykul is a fire giant named Volkhan, who can be seen forging new additions to the iron vrykul army in the Halls of Lightning. Iron vrykul are stored below Forge of Wills, and may be made there, but are not shown being made there. In the end however, it is clear that no matter what the process used to create them, Volkhan is ultimately the "factory worker" building them, while Loken himself is "the boss" that owns them.
World of Warcraft: The Magazine Issue 5 says that the titans created the vrykul, and that the vrykul turned into humans due to the Curse of Flesh, with no other stages mentioned. The iron races are grouped separately.
"That is not dead which can eternal lie
And with strange aeons even death may die"
Ia C'thun! Ia Yogg-Saron! Ia Y'Shaarj! Ia N'zoth! Ia Ny'alotha!
I shall accept our supreme overlords, the world shall kneel. Against them, it is a war that we can not win, we can only delay the inevitable. Go, my fellow mortals, embrace your gods, embrace the Old Gods, we shall tear down the heavens, bring down the Pantheon! For the glory of N'Zoth!
Ia N'Zoth, fhtagn wgah'n shogg!
*clings to his [Puzzlebox of Yogg-Saron]*
What it takes to kill an old god? Saurfang.
I might sound silly here but you could compare an Old God to what we call a recession in economics. You can end (destroy?) a given recession once it takes hold. But you can never truly defeat a recession forever because an economy cannot boom forever. There's always a future recession out there, waiting to manifest (whispering to us all that the good times cannot last forever?)
The Old Gods are never vanquished, just sent into remission a la Freddy Kruger or Jason Voorhees.
Its simple you need dakka. And if that dont work use more dakka.
they dont die, they go play poker with elvis, biggie, tupac, mj and all the other people that arent really dead.