"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, in all likelihood, 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. He had a son in earlier editions, but in 8th edition, his son was retconned out as being dead, so it's inevitable that his line will see its end when he finally perishes. To be exact his Son took the Slayer Oath to exploit a loophole in Dwarven law and tradition then went out and got himself killed to free his line and by extension his father from the oath. However Ungrim despaired about his son's death and re-took the Slayers oath in his grief. (Thus rendering his son's sacrifice pointless.)
On the Tabletop
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