Book of Grudges
The Great Book of Grudges (Dammaz Kron in Khazalid) is a sacred item to the Dwarven folk.
In essence, it's pretty much the place where they record everyone and everything that ever "extremely" wronged them. The book itself came into being since the time when the Dwarfs came into being, and was since then passed down from High King to High King, with the current one being Thorgrim Grudgebearer. Whenever someone did something really horrible, like hiring them to build a palace then refusing to pay them, or attacking a trade cart killing dozens if not hundreds of Dwarfs for no reason other than you didn't like them (and not stealing a keg of beer for example, something ignored in Total War: Warhammer where 'shortchanging them for a palace by two coppers' counts), then that person's name/group's name/army's name/or even race's name would go into the book with the description of the grudge-worthy act.
The good old Dwarven tradition is to settle these grudges the old fashioned way. And by old fashioned, we mean AN AXE TO THE FACE. Alternatively, since Thorgrim is not fucking retarded like most of the other Dwarf kings before him, he lets the act go if they make up for it, like actually getting paid for that palace they didn't get paid to build, even if it is very late in coming. According to Total War: Warhammer they are not above declaring grudges against mountains, literally, for a landslide or something that killed some dwarfs (then again it's the same series where the Orcs are mentioned as collecting Teef and that also doesn't happen in Fantasy). Such a grudge would be settled by strip mining the shit out of the place until nothing useful is left.
When a grudge is settled, it is crossed out. Of course this being Dwarfs, until Thorgrim came along grudges were rarely crossed out even after they were avenged because most Dwarfs consider it more fun to reminisce about the vengeance. In addition, more grudges appear than are settled as each battle means dead Dwarfs or injured equipment, which means more grudges as a cycle of revenge. Due to what's going on in the Old World, these grudges will dramatically grow in numbers.
It is also said that the more of these grudges fill the book, then the Dwarven race is more probable to die out...unless they actually overcome their stubbornness.
Surprisingly, despite all these grudges, you never hear about a Dwarf Book of Grudges running out of pages. Lore implies that at least the High King's book magically either has an endless number of pages or generates more when needed; it's confirmed that the magic allows it to remain the same size and weight no matter how many pages it has.
There was however one situation when a grudge was not written down. When the Dwarfs under Thorgrim Grudgebearer's command met with Tyrion in order to save the High Queen's daughter from Mannfred von Carstein, yet when the vampire escaped with her, Tyrion blamed the Dwarfs for it and insulted them so offensively it was as if he physically struck them. After this the bearded powderkegs urged Thorgrim to write what Tyrion did into the book, yet the High King chose not to, probably seeing it that they might have screwed up. He also didn't want to perpetuate the vicious cycle of vindictiveness. This also shows that Grudgebearer is actually cool-headed for a Dwarf.
List of notable "Extraordinary" individuals recorded in the book
Skarsnik - The one mention having the most entries in the book. A cunning goblin as well as the warlord of the Eight Peaks. Congrats, you filthy grobi, hope Griminir feasts on your dirty greenskin blood, you little shit.
Grimgor Ironhide - Committed several acts of dawi-slaughter with his magic axe Gitsnik, as well as cooking captured Dawi alive inside their armor.
Neferata - The first undead on the list. She invaded and conquered a Dwarf hold, The Silver Pinnacle, and thus began the Dawi hatred for undead.
Malekith - Broke Snorri Whitebeard's promises and caused massive devastation on both elves and dwarfs after he disguised his agents as high elves to assault a dwarf caravan. Apparently has so many grudges against him that a complete record outside the page-generating Book of Grudges would fill libraries (yet still not as many as Skarsnik the aforementioned goblin, who is much younger than Malekith, mind you). Fuck Malekith, you Elgi'drazh piece of shit!
Caledor II - This arrogant Phoenix king is the second reason why the
War of the Beard WAR OF VENGEANCE started. He insulted the Dwarfs when they came to compensate for their lost caravan and even go as far to shave the beard of Grimbok, the Dwarfs emissary that was sent to negotiate. This led Grimbok to become a slayer out of humiliation and Gotrek Starbreaker, the high king at the time had sworn a mighty oath to get the compensation in either gold or blood from the Elves or he else will shave his beard. Such terrifying oaths and tragedies has led Caledor II to have 437 separate grudges against him, along with many insults the Dwarfs created to demean and ridicule him (see below). As of now, this grudge has been avenged with the elf king's death and the high king got the Phoenix Crown in compensation. Still, many grudges against the elven race as a whole remain and the war will forever be remembered as proof that the elves are untrustworthy. He's also acknowledged by both races as CALEDOR THE IDIOT for what he did.
Queek Head-Taker - Killed many Dwarves during his fight for the Karak Eight Peaks as well as wasted an entire armory of expensive, powerful runic weaponry at Karak Azul in a pitch battle where he tricked the Orc of black crag to fight with the dwarves of Karak Azul. His grudge got redeemed in the End Times where Queek was publicly beheaded by Thogrim with his axe during the Skaven siege on Karaz-a-Karak.
Krell - A powerful Khornate champion who had killed many Dwarves in life and death, even sided with the despicable Night Goblins to assault the Dwarf strongholds of Karak Ungor and Karak Varn. His grudge is a notable one since it began in ancient time before the time of Sigmar. Initially, his grudge was suppose to be redeemed after he was slained by a Dwarf hero anmed Grimbul Ironhelm during the assault on Karak Kadrin, he made a return after 1500 years later, raised as an undead wight under the control of the dreaded necromancer Nagash. Even after Krell and Nagash were defeated by Sigamr himself, he made ANOTHER return centuries later, raised by a necromancer named Heinrich Kemmler, the Lichemaster, who now has him as his thrall (until the retcon). Krell finally fucking died after he was beaten down to a soul during a duel with Sigvald, who was punching him in a frenzy after he thought his face was ruined. So yeah, Krell is a badass who is the only individual on this book that had their entry appear 3 TIMES for every time the grudge was redeemed, but actually 5 times if you count The End Times with him finally killed by Sigvald being the 6th times.
Nagash - A very ancient and powerful necromancer who is really, REALLY fucking evil to everyone (even chaos) that not even the book of grudges can ignore him. He is responsible for created vampire (aka Zangunaz) and the undeath in general, created two other extraordinary individual: Krell and Neferata that is already on the list. He was a Nehekhara nobility so he has his own share of Dawi raiding game during his time. His Nine Books of Nagash is made of parts from various species, that include Dawi's beard. He even tried to killed Sigmar, Dwarfs' best friend but failed. He probably had a grudge for every time a random necromancer casted his spell on a Dawi OR raised a Dawi as a living dead. It is also because of him the Tomb kings (aka Uzkuli'gorl) were created and is now haunting every Dawi who had their jewelry as the kings' heirloom or included some of the stolen gold from the kings' in their heirloom.
While the 40k had their own dwarf, they do not have such grudge keeping culture. But it was mentioned that White Scars has this "scroll of vengeance" which they used to record any enemies who had managed escape from their ridiculously speedy bike. These enemies will then be killed by the Master of the Hunt (a particular space marine of the White Scars who is obviously a strong member of the chapter with a high standing such as a captain) during the Great Hunt, its head decapitate, its skull masked in silver and staked along the road that leads through the Khum Karta mountains towards the Palace of Quan Zhou, White Scar's greatest fortress-monastery. Every enemies and their misdeeds on the scrolls is then recited at every quarter of the century by a chaplain during the Rites of Howling with the Chapter Master decided the next target for the great hunt. There is one mentioned the scroll was used by Kor'sarro Khan, where after the events of Escape from Cano'var, he wrote down the name of the necron who killed and imprisoned his battle brothers: Nemesor Zahndrekh and Vargard Obyron.