Tamurkhan: Throne of Chaos
Tamurkhan: Throne of Chaos is a sourcebook released from Forge World, essentially a Warhammer Fantasy Battle equivalent to their "campaign themed" volumes of Imperial Armor. It contains a huge amount of fluff and a bevvy of new rules, units and characters.
The idea of the fluff is the Chaos Gods were sick and tired of this unreliable "Everchosen" shit and just decided to have a Battle Royale to determine who was da biggest and da best, promising the winning champion the "Throne of Chaos" which was to be eternal dominion of the mortal world in a Daemonic Body. Surprisingly Nurgle won because his champion, Tamurkhan showed up a little late to the party and spent that time recruiting many monsters who could handle whatever was thrown at them. Tzeentch's forces fled, sensing Tamurkhans hour was at hand (ironically fleeing might have caused that), the Slaanesh forces were defeated when Tamurkhan killed Sargath the Vain and took his body as his new body, and the Khorne forces were defeated when their leader was eaten by Bile Trolls.
After he was crowned the winner Tamurkhan prepared his assault on The Empire by doing some awesome things, like enslaving Giants, capturing Mammoths, making deals with the Chaos Dwarfs and eventually gaining a total of three armies, as well as trading Sargath's body for the body of an Ogre Tyrant, which unfortunately for him slowly made him dumber over time as a part of the Ogre personality seemed to seep through.
He was eventually defeated outside of Nuln, the final city he needed to take before being granted the Throne of Chaos. After conquering his way all the to it he was met by Nuln's gathered forces, his own horde of miscreants were decimated by short ranged cannon fire and couldn't break through the defenders lines. His second army, specifically an army of Warrior of Chaos were undone when they fought next to a wide, fast flowing river, and they never thought that you could float siege machines down said river and so they had no defence against them and no way to attack them back. The Third army, an army of Chaos Dwarfs got locked in an artillery duel against the defenders of Nuln and after they eventually won were undone by fast cavalry and Marienburg Class Landships. Though they weren't destroyed their leader decided enough Dwarfs had died and didn't want to help anymore so they left. Without Mammoths, Giants, or siege machines Tamurkhan was left without a way to break into the city itself, so he ran away to try and summon a Daemonic Horde. He was eventually counter-attacked by Empire warriors who used a Grey Wizard to teleport themselves over to him and was killed trying to possess the body of Theodore Bruckner, whereupon the amulet given to Bruckner destroyed him.
Narrative Missions: Rules for narrative campaigns in general, and missions specifically reflecting the path of Tamurkhan.
Warriors of Chaos: Rules for the special characters Tamurkhan the Maggot Lord on his Toad Dragon Bubebolous, Sayl the Faithless, Nightmaw, and Kayzk the Befouled, rules for the Rotbeast of Nurgle steed, and rules for the units Chaos Siege Giant, Plague Toads of Nurgle, Bile Trolls of Nurgle, Pox Riders of Nurgle and Chaos War Mammoth.
Empire: Rules for the special characters Theodore Bruckner on Reaper, Lietpold the Black, Captain Edvard Van Der Kraal, Magisterix Elspeth von Draken on a Carmine Dragon, and Castellan-Engineer Jubal Falk, and rules for the new unit Marienburg-class Land Battleship.