Explaining the icc ending

[Alonsus_Faol]

Arthas: He returned to his body for a moment because of frostmourne shattering. His very soul was in the blade along with that of his father and nerzhul. His question was in reference to probably chats he and his father had inside the sword.

Bolvar: The red dragons are the dragons of life. These dragons protect all life and from death they can create life anew. Tunneling undead took bolvars body after it was burned and infected with the plague. His will was far too strong for the Lich King to convert him making him the best canidate.

The Scourge: With it's master gone the scourge will wash over the world destroying all life. This is because the part of Arthas that was still human and loved the world was holding back. Probably there are thousands of more scourge hidden from the world (under da sea). The scourge would then become rabid and feral killing anything in site. They would not regain their wills because of how his mental powers work.
If there will is strong enough and when the incident that occured weakening the Lich King (after the eye was used) those with the strongest wills were free from his control. Now if they are immediately cut from his control all of the scourge would be mindless.(The mindlessness is even exhibited at the frosaken starting zone. Those zombies were said to be Forsaken who lost their minds not scourge.)

How the power was transferred: The Lich King's Crown(Helm of Domination) was where the true power came from.
The helm was crafted to give the wearer extreme mental power. It did not transfer nerzhul's soul as he was in frostmourne.

[Venziir]

Ner'zhul's spirit was bound to the entire suit of armor, and not in Frostmourne. When Arthas placed the Helm of Domination on his head, their spirits fused, thus the whole "Now, we are one!". However, they were not one at all, Arthas had a battle going on inside of him, a battle for control of his mind, soul and body, which he won, by banishing his former self, and the spirit of Ner'zhul. Now that Arthas is dead, and the spirit of Ner'zhul banished, it will be interesting to see what will happen to Bolvar, now that he is the Lich King. The helm was crafted by the Burning Legion, and let's face that fact, that Bolvar is INDEED quite burning, perhaps they will take claim of the Lich King once again? Time will tell.

[Smoopie]

hmm. I didn't know any of that, I don't even read my quests

[Bobzor]

Yea? But why doesn't bolvar destroy the scourge and then stuff that stinky armor somewhere the sun don't shine?

[BruhnDK]

Yea? But why doesn't bolvar destroy the scourge and then stuff that stinky armor somewhere the sun don't shine?

Too hard. Lets take the simple method and let him freeze himself.

[Powerogue]

the original reference to arthas' soul being in the sword:

http://www.youtube.com/watch?v=037gP3t_in4

arthas: yes, i've damned everyone and everything i've ever loved in his name, and yet i still feel no remorse. no shame. no pity
tichondrius: the runeblade that you carry was forged by the lich king [retconned: burning legion] and empowered to steal souls. yours was the first one it claimed
arthas: then i'll make due without one. what is the lich king's will?

[kerwyn]

Yea? But why doesn't bolvar destroy the scourge and then stuff that stinky armor somewhere the sun don't shine?

Why would you destroy a massive army of undead that's calmly under the control of someone on your side when there's an infinite army of demons out there scheming to annihilate your entire planet?