My Speculation on the Coliseum.

[Governor]

In short -

Arthas resurrects Anub'arak, who to redeem himself in the eyes of his king, tunnels deep beneath the newly constructed Coliseum.

Except that Anub'arak hates Arthas, and is working against his own will.

Quote from Wowwiki:

It would appear that Anub'arak is yet another unwilling slave to the Lich King. Currently in Wrath of the Lich King, his quote upon death is, "Ahhh... RAAAAAGH! Never thought... I would be free of him..." This lends credence to what he said to Kel'Thuzad in Path to Damnation, when Kel'Thuzad remarked that in exchange for immortality he had agreed to give himself to the Scourge: "'Agreed' implies choice." retorted Anub'arak.

[Ryuuji]

Saurfang's spirit inside Bolvar's body... that would be badass.

You know not what you say... Do you WISH for the world to be utterly DESTROYED?

[Deleted]

as evry1 now knows, Anub'arak WILL be the last boss in the 10/25 and im guessing the black knight will be the last boss in the 5 man, the lich king destroys the floor in the arena and you start fighting anub'arak

[Ravasha]

as evry1 now knows, Anub'arak WILL be the last boss in the 10/25 and im guessing the black knight will be the last boss in the 5 man, the lich king destroys the floor in the arena and you start fighting anub'arak

You necro.

[arel00]

Anub'arak IS the final raid boss. The Black Knight IS the final 5men boss. Both are on the PTR, so not really new there.

As for the Black Knight being Bolvar... no. He's just a random idiot. I bet Bolvar will be a boss in Icecrown tbh.

[Nathanyel]

I bet Bolvar will be a boss in Icecrown tbh.

Word. A death knight containing the combined souls of Bolvar and Saurfang Jr.

You know, this all won't ring a bell to you at all, but the Lich King and the pre-Lich-King death knights (orc warlocks' souls in human bodies) really reminds me of the negative "super-intelligence" (non-physical higher being, usually a collective of transcended physical beings) KOLTOROC in the German SF series Perry Rhodan.
It was supposed to be a collective of the minds of several members of a humanoid and an insectoid race, to help settle their conflicts, but it was attacked at creation by the Element of Darkness, a non-being/somehow sentient phenomenon of pure darkness, supposedly older than the universe itself (yes there are a great number of Fantasy-like elements, in this case similar to Kil'jaeden's influence as a minion of the ancient Titan Sargeras in the creation of the Lich King) which corrupted the union and perverted the intended combination of opposites (humanoid/insectoid) into a shizophrenic minion of the Powers of Chaos* that was given command over the army/task force TRAITOR**, for which it created the rank of "Dual Captain", a chimera of two physical beings of different races, "sewn" together like siamese twins, each losing one leg and a part of the torso in the process, usually suffering great pain due to the differences in size and shape. Those are modelled after KOLTOROC's avatar, a Dual of a humanoid and an insectoid swarm, as he believes in its insanity that putting together opposites can increase their combined abilities. And it does (though most likely through additional surgery when stitching them up) as the new being can enter the "Singular Intellect", both brains thinking with one mind, in which the Dual can access varying psi powers, most often the Endogene Suffering, which induces great pain in other beings. They also are great tacticians, due to their dual brain power.
What I'm trying to say here is, the concept of combining different characters into one, to enhance or just add their powers, in both cases leads to evil, mad and dangerous foes. :P (Plus, similarities on a larger scale, both universes expand millenia into the past, though of course the SF series usually does that through time travel rather than lore stories, though ancient beings often tell their stories, at least to the reader)

* as opposed to the Powers of Order, though neither qualify for the black and white assignment of "good" and "evil", both have their good points, as well as inhuman methods to reach their goals.
** it's not supposed to mean "traitor", but the creators were of course aware of the English word :P I guess in the end it's just a way to mess with the readers, the term is explained to consist of two words, trai and tor.

[JoeShmoe64]

Saurfang's spirit inside Bolvar's body... that would be badass.

It would also reflect an old-school DK (dying orc's soul in a dead human's body) and the Lich King himself (at least, before the whole Arthas book). We also get an interesting mediator in the Alliance/Horde conflict, with the two of them being one being. I'm a little torn, though, I just want Bolvar to be Bolvar.

Then again, we could immortalize him as an important figure in the ongoing conflict. Eh, either way.

[Teneal]

Unmasked the Black Knight on the PTR. Confirmed that he is Kael'thas.

[Jalzyboo]

Unmasked the Black Knight on the PTR. Confirmed that he is Kael'thas.

Magister's Terrace and The Eye were merely setbacks!