Thrall: Twilight of the Aspects is a World of Warcraft novel by Christie Golden. Basically a follow-up to her earlier The Shattering Prelude To Cataclysm, the book follows the titular ex-Warchief as he struggles with his inner demons, while at the same time the Twilight's Hammer plots to destroy all life on Azeroth, starting with the dragons.
This novel contains examples of:
Absolute Xenophobe: Arygos, proud son of the genocidal Blue Aspect Malygos, hates everyone who isn't a blue dragon, and even wanted to kill Thrall just for being in the Nexus even though he was a on a mission from the other aspects. Of course, it later turns out that he had aligned himself with the Twilight's Hammer.
Alternate Universe: Thrall visits an alternate timeline in the Caverns of Time, where his early death was the point of divergence. Aedelas Blackmoore from this timeline, here usurper king of Lordaeron, is recruited by the Infinite Dragonflight to kill Thrall.
Arc Words: ...Kind of. "All that matters is this moment," while only said once or twice in the book, has been repeated by Nozdormu at least twice more in the World of Warcraft game (including as a greeting).
Cain and Abel: Arygos and Kirygosa, an accomplice to and prisoner of Twilight's Hammer, respectively
The Chains of Commanding: Kalecgos is wary about becoming Blue Aspect, and this enables him to become friends with Thrall, who also had to become Warchief after Doomhammer's death, and realizes that he has been bound by that role.
Cry Cute: Alexstraza, in one of the accompanying illustrations.
Dangerously Genre Savvy: Deathwing. He refuses to rest until he has proof that Thrall the one who has a chance to defeat him is dead. and no, falling off a high cliff does not count.
The Dragon: The Twilight Father is this to Deathwing, and Chromatus is a more literal one once he is awakened.
Eleventh Hour Superpower: Thrall receives powers similar to the Aspect of Earth's to coordinate the Aspects against Chromatus
For Want of a Nail: In the alternate timeline Thrall visits he died young. This leads to Aedelas Blackmoore switching to a better plan, sobering up, killing Orgrim Doomhammer at Blackrock Spire with his mercenaries, and then striking a deal with the orcs in order to usurp the throne of Lordaeron.
Future Me Scares Me: Nozdormu, being the Aspect of Time, has seen that he will some day, in some timeline start the Infinite Dragonflight. He isn't very fond of that idea.
Heroic BSOD: Alexstrasza goes into one after she finds out Korialstrasz was responsible for the destruction of the sanctuaries and all eggs within. She gets better when Thrall reveals that he did it to stop the Twilight corruption (see Heroic Sacrifice below).
Heroic Sacrifice: Korialstrasz/Krasus sacrifices himself to destroy the Wyrmrest sanctuaries and all the corrupted dragon eggs.
Hero Killer: The colossal chromatic dragon Chromatus was bred by Nefarian with this very purpose. In addition, alternate universe Blackmoore is this to Thrall.
Spanner in the Works: Thrall royally fucks up the Twilight Hammer's plan. Though it is partially subverted in that Deathwing is aware of the threat he poses and has made Thrall the top of his hit list
Take That: In an argument with him early in the book, Aggra angrily confronts Thrall about "gossip" regarding potential relationships with Jaina (and before her, Taretha), and tells him off. Considering Golden wrote the novel where Aggra first appeared and sunk the ship, it's hard not to see this as a Take That aimed at Thrall/Jaina shippers.
The End of the World as We Know It: The Hour of Twilight, when all life (except the twilight dragons) will be extinguished and the Old Gods will have won. Fortunately, it is so far only a prophecy.
Tin Tyrant: Alternate Universe Aedelas Blackmoore usurped the throne of Lordaeron, and was then sent by the Infinite Dragonflight to hunt down Thrall. He wears a suit of black armor that incorporates pieces of the Doomhammer armor.