"Not forgiving is like drinking rat poison and then waiting for the rat to die."
- – Anne Lamont
"I must fulfill my slayer oath!"
- – Ungrim Ironfist, summing up his character in a single sentence
Ungrim Ironfist is the most recent - and as of The End Times, the last - Dwarf to hold the title of Slayer King of Karak Kadrin. Heir to the twin oaths of his great-great-great-great-great-granddad, Baragor, Ungrim Ironfist is thusly compelled to both lead his people wisely and safely and to seek out a glorious death in battle. In earlier editions, he had a son; Garagrim Ironfist, but Garagrim decided that he needed to save his father from the Slayer Oath. To this end, Garagrim became his father's War-Mourner - a dwarven champion whose honor and the king's are one, and pursued the life of a Slayer. He planned to exploit the loophole that, as War-Mourner, if Garagrim was killed under the Slayer Oath, his father and any future sons would be free of the Slayer Oath, ending the reign of the tormented Slayer Kings.
Then eight edition came along and said that Garagrim had succeeded in dying a heroic death, perhaps a nod to the Storm of Chaos.... And Ungrim promptly took up a NEW Slayer Oath out of his grief at Garagrim's death, rendering his son's sacrifice absolutely fucking pointless!
But then again, if Warhammer dwarves were smart, they wouldn't be as badly off as they were.
On the Tabletop
Ungrim Ironfist made an appearance in the Storm of Chaos army book, a Special Character and mandatory general available to both the normal Dwarf and to the Slayers of Karak Kadrin army, where he uses up a Lord slot AND a Hero slot. He has Movement 3, WS 7, BS 4, S 4, T 5, W 3, I 5, A 4 and LD 10. He wears Gromril Armor (Armor Save 4+), the Dragon Cloak of Karak Kadrin, and the Slayer Crown, and wields the Axe of Dargo. He costs 465 points and has the special rule Slayer King, which is a variant of the normal Slayer rule; he gets the bonus powers of Slayer, Hates Greenskins and is Unbreakable, but the other attributes of Slayer do not apply to him.
The Dragon Cloak of Karak Kadrin bears a Master Rune of Spite (4+ Ward Save), a Rune of the Furnace (Ungrim is Immune to Fire), and a Rune of Luck (Ungrim may re-roll a single dice per battle).
The Axe of Dargo bears the Master Rune of Smiting (successful Wounds inflict d6 Wounds) and a Rune of Parrying (Ungrim can nullify one enemy attack in close combat).
The Slayer Crown bears a Rune of Fortitude (+1 Wound, so Ungrim has 4 Wounds) and a Rune of Stone (+1 Armor Save, boosting his Gromril Armor to a 3+ Armor Save).
Ungrim Ironfist is a melee monster. Though slow as any Dwarf, his WS 9, S4, I5 4 Attacks are made with the Axe of Dargo, which means he's dishing out Killing Blow attacks with +2 to his Strength. When it comes to survival, he wears gromril armor and the Slayer Crown (which adds +1 to armor save and boosts his Toughness by +1, making him T6), not to mention the Dragon Cloak of Fyrskar (Ward Save 4+, improves to 2+ against Flaming Attacks) and sports 3 Wounds, so he doesn't go down easily. He's got the special rules Ancestral Grudge, Daemon Slayer, Deathblow, Dragon Slayer, Relentless, Resolute, Slayer, Unbreakable, and the unique rule of Slayer King. This means he can only join Slayer units, but he can still be the Army General. If he leads the army, a single Slayer unit may take a runic standard of up to 100 points.
In The End Times
So, Ungrim's pretty killy as he is. But what if he could burninate stuff too? The End Times decided they'd let folks find out, by having Aqshy, the Wind of Fire, latch onto Ungrim's soul and make him the living avatar of flame.
Ungrim the Slayer, Incarnate of Fire, starts with Ungrim himself. It then pumps him up with +1 to Strength, Wounds and Attacks, gives him a Strength 4 Flaming Attacks Breath Weapon, and an innate bound spell (power level 5) called Lord of Fire, that lets him fling a 2D6 S4 Flaming Attacks magic missile a range of 24".
Ungrim in Total War: WARHAMMER